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Photochemical & Photobiological Sciences

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https://www.readbyqxmd.com/read/28210728/self-initiation-of-uv-photopolymerization-reactions-using-tetrahalogenated-bisphenol-a-meth-acrylates
#1
Théophile Pelras, Wolfgang Knolle, Sergej Naumov, Katja Heymann, Olesya Daikos, Tom Scherzer
The potential of tetrachlorinated and tetrabrominated bisphenol A diacrylates and dimethacrylates for self-initiation of a radical photopolymerization was investigated. The kinetics of the photopolymerization of an acrylic model varnish containing halogenated monomers was studied by real-time FTIR spectroscopy, whereas the formation of reactive species and secondary products was elucidated by laser flash photolysis and product analysis by GC-MS after steady-state photolysis. The interpretation of the experimental data and the analysis of possible reaction pathways were assisted by quantum chemical calculations...
February 17, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28203671/heat-shock-antagonizes-uva-induced-responses-in-murine-melanocytes-and-melanoma-cells-an-unexpected-interaction
#2
Leonardo Vinícius Monteiro de Assis, Maria Nathália Moraes, Ana Maria de Lauro Castrucci
The skin is under the influence of oscillatory factors such as light and temperature. This organ possesses a local system that controls several aspects in a time-dependent manner; moreover, the skin has a well-known set of opsins whose function is still unknown. We demonstrate that heat shock reduces Opn2 expression in normal Melan-a melanocytes, while the opposite effect is found in malignant B16-F10 cells. In both cell lines, UVA radiation increases the expression of Opn4 and melanin content. Clock genes and Xpa, a DNA repair gene, of malignant melanocytes are more responsive to UVA radiation when compared to normal cells...
February 16, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28186216/absolute-configuration-determination-through-the-unique-intramolecular-excitonic-coupling-in-the-circular-dichroisms-of-o-p-ddt-and-o-p-ddd-a-combined-experimental-and-theoretical-study
#3
Hiroki Tanaka, Yoshihisa Inoue, Takeshi Nakano, Tadashi Mori
Circular dichroisms (CDs) of the o,p'-isomers of 1,1,1-trichloro- and 1,1-dichloro-2,2-bis(chlorophenyl)ethanes (DDT and DDD) were investigated experimentally and theoretically. A series of strong Cotton effect peaks in a characteristic negative-negative-positive-negative, or its mirror-imaged, pattern were observed in the CD spectra of these persistent organic pollutants. The theoretical CD spectra at the SAC-CI/B95(d) and RI-CC2/def2-TZVPP levels well reproduced the experimental ones, enabling us to unambiguously assign the absolute configuration of (+)-DDT and (-)-DDD as S...
February 10, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28165094/exfoliation-and-supramolecular-functionalization-of-graphene-with-an-electron-donor-perylenediimide-derivative
#4
Luis Martín-Gomis, Nikos Karousis, Fernando Fernández-Lázaro, Ioannis D Petsalakis, Kei Ohkubo, Shunichi Fukuzumi, Nikos Tagmatarchis, Ángela Sastre-Santos
The liquid exfoliation of graphite to few layered graphene sheets together with the non-covalent supramolecular functionalization of exfoliated graphene by the synthesized N,N'-di(2-ethylhexyl)-1-(N''''-methylpiperazin-N'''-yl)perylene-3,4,9,10-tetracarboxydiimide (Pip-PDI) is reported. The aromatic Pip-PDI has the ability to non-covalently interact with the exfoliated graphene sheets, stabilizing them and preventing their reassembly. On the other hand, the presence of the piperazine moiety on the bay position of the PDI core makes it an ideal electron donor, nicely coupled with the electron accepting exfoliated graphene, hence, forming a novel donor-acceptor nanoensemble, which was characterized by complementary spectroscopic and microscopy techniques...
February 6, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28155961/homoleptic-complexes-of-a-porphyrinatozinc-ii-2-2-6-2-terpyridine-ligand
#5
Angelo Lanzilotto, Martin Kuss-Petermann, Oliver S Wenger, Edwin C Constable, Catherine E Housecroft
Three homoleptic complexes containing the metalloligand 7-(4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)-5,10,15,20-tetraphenylporphyrinatozinc(ii), 1, have been prepared. [Zn(1)2][PF6]2, [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2 were characterized by (1)H and (13)C NMR spectroscopy and mass spectrometry, and the electrochemical and photophysical properties of the complexes have been investigated. In solution, each complex undergoes two reversible porphyrin-centred oxidation processes, with an additional reversible metal-centred oxidation for [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2...
February 3, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28154871/introduction-to-the-themed-issue-the-health-benefits-of-uv-radiation-exposure-through-vitamin-d-production-or-non-vitamin-d-pathways
#6
EDITORIAL
Prue H Hart, Mary Noval, Vivienne E Reeve
No abstract text is available yet for this article.
February 3, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28150847/ylidenemalononitrile-enamine-coated-media-as-fluorescent-turn-on-probes-for-volatile-primary-amines
#7
Ashley R Longstreet, Rebecca R Chandler, Tanmay Banerjee, L Zane Miller, Kenneth Hanson, D Tyler McQuade
Two ylidenemalononitrile enamines, adsorbed to various media, undergo a cyclization reaction with primary amine vapors resulting in a fluorometric and colorimetric response. After determining the media with the fastest response rate for emission "turn-on" to be aluminum oxide activated neutral (AON), we further demonstrate the sensitivity (propylamine concentrations as low as 200 ppm are detected) and selectivity to various analytes including amines, methanol, and ethanethiol. Lastly, as an alternative means of detection, the colorimetric response dye on glass filter paper was shown to detect propylamine concentrations as low as 29 ppm...
February 2, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28145542/a-spectroscopic-study-of-the-excited-state-proton-transfer-processes-of-8-bromo-7-hydroxyquinolin-2-yl-methyl-protected-phenol-in-aqueous-solutions
#8
Jinqing Huang, Adna P Muliawan, Jiani Ma, Ming De Li, Hoi Kei Chiu, Xin Lan, Davide Deodato, David Lee Phillips, Timothy M Dore
A combination of spectroscopic methods and density functional theory (DFT) computations was used to study the excited state proton transfer (ESPT) processes of (8-bromo-7-hydroxyquinolin-2-yl)methyl-protected phenol (BHQ-OPh). Characterization of the prototropic forms of BHQ-OPh in different solvent environments revealed that the neutral form predominates in acetonitrile and in 1 : 1 acetonitrile/water (pH 5.0), whereas the anionic form predominates in 1 : 1 acetonitrile/PBS (pH 7.4). Both the neutral and anionic forms were significantly populated in 1 : 1 acetonitrile/water...
February 1, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28139795/sunlight-exposure-is-just-one-of-the-factors-which-influence-vitamin-d-status
#9
M Abboud, M S Rybchyn, R Rizk, D R Fraser, R S Mason
Studies on the determinants of vitamin D status have tended to concentrate on input - exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D...
January 31, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28138687/serum-endocannabinoids-and-n-acyl-ethanolamines-and-the-influence-of-simulated-solar-uvr-exposure-in-humans-in-vivo
#10
Sarah J Felton, Alexandra C Kendall, Abdalla F M Almaedani, Paula Urquhart, Ann R Webb, Richard Kift, Andy Vail, Anna Nicolaou, Lesley E Rhodes
Solar ultraviolet radiation (UVR) exposure of human skin has beneficial and harmful effects on health, including impact on immune function, inflammation and reportedly mood, but these are not fully elucidated. Since the endocannabinoid system is implicated in many activities including mood alteration, our objective was to (i) determine and quantify circulating levels of a wide range of endocannabinoid and N-acyl ethanolamine (NAE) species (ii) evaluate whether these are modulated by cutaneous UVR exposures, as attained through repeated low level summer sunlight exposure...
January 31, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28134378/photochemical-synthesis-and-photophysical-properties-of-coumarins-bearing-extended-polyaromatic-rings-studied-by-emission-and-transient-absorption-measurements
#11
Minoru Yamaji, Yuma Hakoda, Hideki Okamoto, Fumito Tani
We prepared a variety of coumarin derivatives having expanded π-electron systems along the direction crossing the C3-C4 bond of the coumarin skeleton via a photochemical cyclization process and investigated their photophysical features as a function of the number (n) of the added benzene rings based on emission and transient absorption measurements. Upon increasing n, the fluorescence quantum yields of the π-extended coumarins increased. Expanding the π-electron system on the C3-C4 bond of the coumarin skeleton was found to be efficient for increasing the fluorescence ability more than that on the C7-C8 bond...
January 30, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28125108/low-level-laser-therapy-alters-satellite-glial-cell-expression-and-reverses-nociceptive-behavior-in-rats-with-neuropathic-pain
#12
M E Oliveira, F M Santos, R P Bonifácio, M F Freitas, D O Martins, M Chacur
BACKGROUND: Nerve injury often results in persistent or chronic neuropathic pain characterized by spontaneous burning pain accompanied by allodynia and hyperalgesia. Low level laser therapy (LLLT) is a noninvasive method that has proved to be clinically effective in reducing pain sensitivity and consequently in improving the quality of life. Here we examined the effects of LLLT on pain sensitivity induced by chronic constriction injury (CCI) in rats. CCI was performed on adult male rats, subjected thereafter to 10 sessions of LLLT, every other day, and starting 14 days after CCI...
January 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28124708/environmental-effects-of-ozone-depletion-and-its-interactions-with-climate-change-progress-report-2016
#13
United Nations Environment Programme Environmental Effects Assessment Panel
The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed...
January 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28124059/synthesis-and-photophysical-properties-of-extended-%C3%AF-conjugated-naphthalimides
#14
C Rémy, C Allain, I Leray
A series of π conjugated naphthalimide derivatives having an imide group as an acceptor conjugated with a methoxy arylethynyl or a methoxyphenyl triazole as a donor were prepared by Sonogashira coupling or "click" chemistry. Their photophysical properties were investigated by steady state and time resolved fluorescence spectroscopy and modelled by TD-DFT calculations. Compound Naphth-AlkyneOMe has a high fluorescence quantum yield and displays efficient photoinduced charge transfer in solution as well as in the powder state...
January 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28102421/the-nature-of-the-light-absorption-and-emission-transitions-of-4-hydroxybenzophenone-in-different-solvents-a-combined-computational-and-experimental-study
#15
Francesco Barsotti, Giovanni Ghigo, Silvia Berto, Davide Vione
The photophysics and photochemistry of 4-hydroxybenzophenone (4HOBP) are interesting because they can give some insight into the behavior of humic material. Here we show that 4HOBP has a number of fluorescence peaks: (i) an intense one at excitation/emission wavelengths Ex/Em ∼ 200-230/280-370 nm, likely due to an excitation transition from S0 to S5 or S6, followed by S2 → S0 in emission (Sn denotes the singlet states of 4HOBP); (ii) a minor peak at Ex/Em ∼ 270-300/320-360 nm (S0 → S2 in absorption and S2 → S0 in emission), and (iii) very interesting signals in the typical emission region of humic substances, most notably at Ex/Em ∼ 200-220/400-500 nm and Ex/Em ∼ 260-280/400-470 nm (in both cases the emission corresponded to an S1 → S0 transition)...
January 19, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28102417/does-sunlight-protect-us-from-cancer
#16
Jacqueline E Marshall, Scott N Byrne
The Ultraviolet (UV) radiation contained in sunlight is a powerful mutagen and immune suppressant which partly explains why exposure to solar UV is the biggest risk factor for the development of cutaneous tumours. Evidence is building that sunlight may be protective against some internal malignancies. Because patients with these tumours are often vitamin D deficient, this has led some to propose that vitamin D supplementation will be beneficial in the treatment of these cancers. However, the results from already completed trials have been disappointing which has given weight to the argument that there must be something else about sunlight that explains its cancer-protecting properties...
January 19, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28092390/asthma-comparing-the-impact-of-vitamin-d-versus-uvr-on-clinical-and-immune-parameters
#17
Kylie A Morgan, Elizabeth H Mann, Antony R Young, Catherine M Hawrylowicz
The incidence of asthma has increased markedly since the 1960s and is currently estimated to affect more than 300 million individuals worldwide. A number of environmental factors are implicated in asthma pathogenesis, one of which is vitamin D. Vitamin D deficiency is a global health concern and has increased in parallel with asthma incidence. Epidemiological studies report associations between low vitamin D status, assessed as circulating levels of 25-hydroxyvitamin D, with asthma incidence, severity, exacerbations and responses to treatment...
January 16, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28091662/self-assembly-optical-thermal-and-electrochemical-properties-of-bis-n-benzyl-perylene-diimide-dye
#18
Devrim Ozdal, Nur P Aydinlik, Jagadeesh B Bodapati, Huriye Icil
Flexible methylene containing N,N'-bis-(benzyl)-3,4,9,10-perylenebis(dicarboximide) (1) was synthesized. Self-assembled microstructures (hollow tubes, average length and width: 7.7 and 0.8 μm) of 1 were also prepared (T-1). Comparative studies of the optical, thermal and electrochemical properties of 1 and T-1 have been extensively carried out. The T-1 hallow tubes have shown extremely broad absorption in the near-infrared (300-800 nm) region (NIR) even in solution and intensified conductivity in the solid-state compared to 1...
January 16, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28078341/the-role-of-uv-radiation-and-vitamin-d-in-the-seasonality-and-outcomes-of-infectious-disease
#19
Abhimanyu, Anna K Coussens
The seasonality of infectious disease outbreaks suggests that environmental conditions have a significant effect on disease risk. One of the major environmental factors that can affect this is solar radiation, primarily acting through ultraviolet radiation (UVR), and its subsequent control of vitamin D production. Here we show how UVR and vitamin D, which are modified by latitude and season, can affect host and pathogen fitness and relate them to the outcomes of bacterial, viral and vector-borne infections...
January 12, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28074966/the-relationship-between-sun-exposure-and-all-cause-mortality
#20
Pelle G Lindqvist, Mona Landin-Olsson
We aimed to conduct a narrative review of the rapid advances in knowledge regarding sun exposure and all-cause mortality. Data support the hypothesis that sun exposure avoidance is a major risk factor for all-cause mortality in adjusted analysis (age, income, education, marital status, smoking, and comorbidity). This was caused by an increased risk of death due to cardiovascular disease (CVD) and noncancer/non-CVD. However, the increased life span among those with high sun exposure naturally results in an increased prevalence of cancer death...
January 11, 2017: Photochemical & Photobiological Sciences
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