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Photochemistry and Photobiology

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https://read.qxmd.com/read/30767232/erythemal-uv-radiation-on-days-with-low-uv-index-values-an-analysis-of-data-from-the-german-solar-uv-monitoring-network-over-a-ten-year-period
#1
Maria Lehmann, Henner Sandmann, Annette B Pfahlberg, Wolfgang Uter, Olaf Gefeller
According to the World Health Organization and partner organizations, no protection against ultraviolet (UV) radiation is required on days with 'low' values (i.e. values of less than 3) of the Global Solar Ultraviolet Index (UVI). Erythemal irradiance (Eer ) data of such days were analyzed to evaluate this claim. Measurements from 9 stations of the German solar UV monitoring network from 2007 to 2016 yielded 14,431 daily Eer time series of low UVI days. Erythemal doses for certain fixed time intervals - acquired from measurements on horizontal planes - were compared with the average minimal erythemal dose (MED) of skin phototype II...
February 15, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30767226/ferrochelatase-deficiency-abrogated-the-enhancement-of-aminolevulinic-acid-mediated-protoporphyrin-ix-by-iron-chelator-deferoxamine
#2
Pratheeba Palasuberniam, Daniel Kraus, Matthew Mansi, Alexander Braun, Richard Howley, Kenneth A Myers, Bin Chen
Aminolevulinic acid (ALA) is a prodrug that is metabolized in the heme biosynthesis pathway to produce protoporphyrin IX (PpIX) for tumor fluorescence detection and photodynamic therapy (PDT). The iron chelator deferoxamine (DFO) has been widely used to enhance PpIX accumulation by inhibiting the iron-dependent bioconversion of PpIX to heme, a reaction catalyzed by ferrochelatase (FECH). Tumor response to DFO treatment is known to be highly variable and some tumors even show no response. Given the fact that tumors often exhibit reduced FECH expression/enzymatic activity, we examined how reducing FECH level affected the DFO enhancement effect...
February 15, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30701558/a-cyanine-photooxidation-%C3%AE-elimination-sequence-enables-near-infrared-uncaging-of-aryl-amine-payloads
#3
Tsuyoshi Yamamoto, Donald R Caldwell, Albert Gandioso, Martin J Schnermann
Uncaging strategies that use near-infrared (NIR) wavelengths can enable the highly targeted delivery of biomolecules in complex settings. Many methods, including an approach we developed using cyanine photooxidation, are limited to phenol-containing payloads. Given the critical role of amines in diverse biological processes, we sought to use cyanine photooxidation to initiate the release of aryl amines. Heptamethine cyanines substituted with an aryl amine at the C4' position undergo only inefficient release, likely due electronic factors...
January 30, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30689211/influence-of-air-temperature-on-the-uv-exposure-of-different-body-sites-due-to-clothing-of-young-women-during-daily-errands
#4
Alois W Schmalwieser, Veronika T Schmalwieser, Susanne S Schmalwieser
Clothing is one of the main influencing factors for personal ultraviolet radiation (UVR) exposure. Despite that, little attention was put on this topic till now. In this study, the clothing habits of young females have been investigated in dependence of meteorological conditions. Observations were made from spring to autumn during daylight in the urban region of Vienna, Austria. For this, a scheme dividing the body into 6 different sections was developed as well as a coding scale that corresponds to the different garments and indicates the body sites that are exposed...
January 28, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30689210/nlophoric-triphenylamine-derived-donor-%C3%AF-acceptor-%C3%AF-donor-based-colorants-synthesis-spectroscopic-density-functional-theory-and-z-scan-studies
#5
Manish M Raikwar, Elizabeth Mathew, Manu Varghese, Issac H Joe, Sekar Nagaiyan
Three Donor-π-Acceptor-π-Donor type styryl dyes (5a-c) with different secondary donors are synthesized and characterized to study their non-linear and linear optical properties. The structure-property relationships of the dyes are described in the light of systematic photophysical and theoretical investigations. The photophysical characteristics of 5a-c are influenced by the polarity of the medium, with an appreciable bathochromic shift in emission (5b = 81 nm) and large Stoke shifts (5b = 104-173 nm) in polar solvents...
January 28, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30663066/cutaneous-photoprotective-activity-of-a-short-term-ingestion-of-high-flavanol-cocoa-a-nutritional-intervention-study
#6
Piergiacomo Calzavara-Pinton, Irene Calzavara-Pinton, Mariachiara Arisi, Maria Teresa Rossi, Giovanni Scapagnini, Sergio Davinelli, Marina Venturini
In vivo and in vitro studies have shown that prolonged oral administration of flavanol rich cocoas extracts have photoprotective effects. The aim of the present study is to assess the photoprotective activity of short-time administration of a new variety of naturally selected cocoa extract rich in bioactive compounds. We selected a cocoa powder particularly rich in polyphenols, flavanols, caffeine, theobromine and theophylline. We then investigated, in 10 healthy subjects, the photoprotective effects of one week of daily oral administration of two doses of such powder...
January 20, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30649836/sunshine-is-an-important-determinant-of-vitamin-d-status-even-among-high-dose-supplement-users-secondary-analysis-of-a-randomised-controlled-trial-in-crohn-s-disease-patients
#7
Fiona O'Sullivan, Tara Raftery, Michiel van Weele, Jos van Geffen, Deirdre McNamara, Colm O'Morain, Nasir Mahmud, Dervla Kelly, Martin Healy, Maria O'Sullivan, Lina Zgaga
Sunshine is considered to be the most important source of vitamin D. Due to an increased risk of skin cancer, sun avoidance is advised, but this directly contributes to the high prevalence of vitamin D deficiency. The simple solution is to advise vitamin D supplementation. The aim of this study is to examine the absolute and relative contribution of sunshine and supplementation to vitamin status. This study was a secondary analysis of an RCT of 92 Crohn's disease patients in remission (49% female, median age=44)...
January 16, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30636041/highly-sensitive-and-selective-fluorescence-probe-for-2-4-dinitrophenylhydrazine-detection-in-wastewater-using-water-soluble-cdte-qds
#8
Qiuyue Wang, Xuehan Wang, Yiwei Wu
A simple, cheap, sensitive and selective probe for determination of DNPH in wastewater using thioglycolic acid (TGA)-coated CdTe QDs (TGA-QDs) as fluorescence probe have been established and the properties of CdTe QDs were characterized by TEM, FT-IR, DLS, XRD and zeta potentials. CdTe QDs fluorescence is highly efficiently quenched after adding DNPH on account of electron transfer effect, and the fluorescence quenching behavior of CdTe QDs interaction with DNPH is static quenching process. A good linear relationship is observed between the relative fluorescence intensity (F0 /F) and 0...
January 12, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30636010/photoprotective-and-antigenotoxic-effects-of-the-flavonoids-apigenin-naringenin-and-pinocembrin
#9
Adriana García Forero, Diego Armando Villamizar Mantilla, Luis A Núñez, Raquel Elvira Ocazionez, Elena E Stashenko, Jorge Luis Fuentes
This work evaluated the photoprotective and antigenotoxic effects against ultraviolet B (UVB) radiation of flavonoid compounds apigenin, naringenin and pinocembrin. The photoprotective efficacy of these compounds was estimated using in vitro photoprotection indices, the antigenotoxicity against UVB radiation was evaluated using the SOS Chromotest and an enzymatic (proteinase K/T4 endonuclease V enzyme) Comet assay in UV-treated Escherichia coli and human (HEK-293) cells, respectively. Naringenin and pinocembrin showed maximum UV-absorption peak in UVC and UVB zones; while apigenin showed UV-absorption capability from UVC to UVA range...
January 12, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30636002/differential-photosynthetic-response-of-a-green-tide-alga-ulva-linza-to-ultraviolet-radiation-under-short-and-long-term-ocean-acidification-regimes
#10
Jing Ma, Liming Qu, Wen Wang, Xiaoyan Liu, Sen Qiao, Hailong Wu, Guang Gao, Juntian Xu
Both ocean acidification (OA) and solar ultraviolet (UV) radiation can bring about changes in macroalgal physiological performance. However, macroalgal responses to UV radiation when acclimatized to OA under different time scales are rare. Here, we investigate the response of Ulva linza, a green tide alga, to UV radiation in the form of photosynthetically active radiation (PAR) or PAB (PAR+UVA+UVB) radiation. Radiation exposures were assessed following long-term (from spore to adult stage, one month) and short-term (adult stage, one week) OA treatments...
January 12, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30623466/seasonal-minimum-and-maximum-solar-ultraviolet-exposure-measurements-of-classroom-teachers-residing-in-tropical-north-queensland-australia
#11
Nathan J Downs, Damien P Igoe, Alfio V Parisi, Olivia Taylor, Shari L Lazzaroni, Alex Rawlings, Daniel R Garzón-Chavez, Simone L Harrison
The risk of keratinocyte skin cancer, malignant melanoma and ultraviolet radiation (UVR)-induced eye disease is disproportionately higher in Australia and New Zealand compared to equivalent northern hemisphere latitudes. While many teachers are aware of the importance of reinforcing sun-safety messages to students, many may not be aware of the considerable personal exposure risk while performing outdoor duties in locations experiencing high to extreme ambient-UVR year-round. Personal erythemally-effective exposure of classroom teachers in tropical Townsville (19...
January 8, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30613996/efficient-photooxidation-of-aryl-hetaryl-pyrazolines-by-benzoquinone
#12
Valery F Traven, Ivan V Ivanov, Sergei M Dolotov, Artem N Semakin, Dmitriy A Cheptsov, Zarina Z Mamirgova
Photooxidation of aryl(hetaryl)pyrazolines in the presence of benzoquinone has been studied in organic solvents. This reaction occurs at high rate to provide the corresponding pyrazole in a good yield. The effects of the solvent, pyrazoline structure and oxygen provide definite information on the reaction pathway. It appears that radical species are intermediates in the photooxidation of aryl(hetaryl)pyrazolines in the presence of benzoquinone. A comparison of the new results with the photooxidation of aryl(hetaryl)pyrazolines in the presence of perchloroalkanes is also discussed...
January 6, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30613988/photo-modification-of-melanin-by-a-mid-infrared-free-electron-laser
#13
Takayasu Kawasaki, Aomi Sato, Yuki Tominaga, You Suzuki, Takahiro Oyama, Makoto Tadokoro, Koichi Tsukiyama, Kiyoshi Nokihara, Heishun Zen
Melanin is rigidly constructed by several nitrogen-containing aromatic rings, and its excess accumulation in skin tissue is closely associated with melanosis. Although visible lasers (wavelength: 600-1000 nm) are conventionally used for the photo-thermolysis of melanocyte, several pigmented nevi are difficult to be treated. Here, we propose an alternate method for targeting the molecular structure of melanin using an infrared free electron laser (FEL) tuned to 5.8 μm that corresponds to the stretching vibrational mode of carboxylate group...
January 5, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30613987/bystander-me45-melanoma-cells-increase-damaging-effect-in-uvc-irradiated-cells
#14
Aleksandra Krzywon, Maria Widel
The aim of our study was to investigate the possible mechanism(s) of the bystander effect induced by UVC light in malignant melanoma Me45 cells that were co-incubated with irradiated cells of the same line. We have found that the UVC band effectively generated apoptosis, premature senescence, single and double DNA strand breaks and reduced clonogenic survival of bystander cells. However, in the feedback response, the bystander cells intensified damage in directly irradiated cells, especially seen at the level of apoptosis and survival of clonogenic cells...
January 4, 2019: Photochemistry and Photobiology
https://read.qxmd.com/read/30592312/effect-of-titanium-dioxide-film-thickness-on-photocatalytic-and-bactericidal-activities-against-listeria-monocytogenes
#15
Marion Barthomeuf, Xavier Castel, Laurent Le Gendre, Justine Louis, Martine Denis, Christine Pissavin
Structural, microstructural and bactericidal surface properties of TiO2 -coated glass substrates elaborated by reactive RF-sputtering are investigated. As pathogenic bacteria in biofilms are a major concern in food industries due to their growing resistance to cleaning and sanitizing procedures, the development of photoactive surfaces exhibiting bactericidal properties is acknowledged as an effective approach to tackle bacterial contaminations. Our principal aim concerns the study of the photoactive top-layer thickness impact (from 80 nm to ~500 nm) on Listeria monocytogenes...
December 28, 2018: Photochemistry and Photobiology
https://read.qxmd.com/read/30585639/shining-light-on-the-secreted-luciferases-of-marine-copepods-current-knowledge-and-applications
#16
Svetlana V Markova, Marina D Larionova, Eugene S Vysotski
Copepod luciferases - a family of small secretory proteins of 18.4-24.3 kDa, including a signal peptide, are responsible for bright secreted bioluminescence of some marine copepods. The copepod luciferases use coelenterazine as a substrate to produce blue light in a simple oxidation reaction without any additional cofactors. They do not share sequence or structural similarity with other identified bioluminescent proteins including coelenterazine-dependent Renilla and Oplophorus luciferases. The small size, strong luminescence activity and high stability, including thermostability, make secreted copepod luciferases very attractive candidates as reporter proteins which are particularly useful for nondisruptive reporter assays and for high-throughput format...
December 26, 2018: Photochemistry and Photobiology
https://read.qxmd.com/read/30582757/comparative-study-of-the-effects-of-fech-sirna-transfection-mediated-by-ultrasound-microbubbles-and-pei-in-combination-with-low-dose-ala-to-enhance-ppix-accumulation-in-human-endometrial-cancer-xenograft-nude-mice-models
#17
Xian Zhang, Longfei Chen, Lvfen Gao, Xuesong Gao, Nan Li, Yuwei Song, Xinke Huang, Shaoqiang Lin, Xiaoyu Wang
Comparison of the fluorescence intensity caused by the accumulation of PpIX in endometrial cancer xenografts in nude mice after low-dose ALA injection combined with siRNA transfection was mediated by ultrasound microbubbles and PEI to explore the feasibility of the ultrasound microbubble technique as transfection agents. Knockdown of FECH in human endometrial cancer xenografts in nude mice was performed by transfection with FECH-siRNA mediated by PEI and ultrasound microbubbles alone or in combination, then low-dose ALA was injected...
December 24, 2018: Photochemistry and Photobiology
https://read.qxmd.com/read/30582615/structural-and-functional-consequences-of-the-weak-binding-of-chlorin-e6-to-bovine-rhodopsin
#18
James Mitchell, Naveena Yanamala, Yi Lei Tan, Eric E Gardner, Kalyan C Tirupula, Fernanda Balem, Mordechai Sheves, Daniel Nietlispach, Judith Klein-Seetharaman
The chlorophyll-derivative chlorin e6 (Ce6) identified in the retinas of deep-sea ocean fish is proposed to play a functional role in red bioluminescence detection. Fluorescence and 1 H NMR spectroscopy studies with the bovine dim-light photoreceptor, rhodopsin, indicate that Ce6 weakly binds to it with μM affinity. Absorbance spectra prove that red light sensitivity enhancement is not brought about by a shift in the absorbance maximum of rhodopsin. 19 F NMR experiments with samples where 19 F labels are either placed at the cytoplasmic binding site or incorporated as fluorinated retinal, indicate that the cytoplasmic domain is highly perturbed by binding, while little to no changes are detected near the retinal...
December 24, 2018: Photochemistry and Photobiology
https://read.qxmd.com/read/30580440/photostability-of-terbinafine-under-uva-irradiation-the-effect-of-uv-absorbers
#19
Agata Kryczyk-Poprawa, Paweł Żmudzki, Paulina Koczurkiewicz, Elżbieta Pękala, Urszula Hubicka
The photostability of drugs administered topically on unprotected skin is a complex phenomenon that could be connected with the loss of activity or, rather rarely, the occurrence of toxic degradation products. In this study, an in-depth investigation of the photostability of terbinafine, in both solutions and formulations, was conducted, taking into account the presence of UV absorbers such as TiO2 , ZnO, avobenzone, 3-(4-methylbenzylidene)camphor, octocrylene, benzophenone-1 and benzophenone-2. The clear photocatalytic degradation of terbinafine in ethanol solution was observed in the presence of TiO2 and/or ZnO...
December 22, 2018: Photochemistry and Photobiology
https://read.qxmd.com/read/30548616/two-consecutive-polar-amino-acids-at-the-end-of-helix-e-are-important-for-fast-turnover-of-the-archaerhodopsin-photocycle
#20
Xiong Geng, Gang Dai, Luomeng Chao, Durige Wen, Takashi Kikukawa, Tatsuo Iwasa
Archaerhodopsins (ARs) is one of the members of microbial rhodopsins. Threonine 164 (T164) and serine 165 (S165) residues of the AR from Halorubrum sp. ejinoor (HeAR) are fully conserved in ARs, although they are far from the proton transfer channel and the retinal Schiff base, and are likely involved in a hydrogen bonding network at the end of the Helix E where most microbial rhodopsins assume a "bent structure". In the present work, T164 and/or S165 were replaced with an alanine (A), and the photocycles of the mutants were analyzed with flash photolysis...
December 12, 2018: Photochemistry and Photobiology
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