Free radical involvement in long wavelength UV light activation of nitrosamines to mutagens

1986 ◽  
Vol 5 (2) ◽  
pp. 109-127 ◽  
Author(s):  
Edward J. Webman ◽  
Thomas A. Grover ◽  
Hikoya Hayatsu ◽  
Howard F. Mower
Keyword(s):  
Free Radical ◽  
Uv Light ◽  
Light Activation ◽  
Long Wavelength

scholarly journals The Applicability of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile Sensors for Monitoring Different Types of Photopolymerization Processes and Acceleration of Cationic and Free-Radical Photopolymerization Under Near UV Light

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1668 ◽  
Author(s):  
Joanna Ortyl ◽  
Paweł Fiedor ◽  
Anna Chachaj-Brekiesz ◽  
Maciej Pilch ◽  
Emilia Hola ◽  
...  
Keyword(s):  
Free Radical ◽  
Fluorescence Probe ◽  
Uv Light ◽  
Molecular Sensors ◽  
Long Wavelength ◽  
Free Radical Photopolymerization ◽  
Cationic Photopolymerization ◽  
Different Types ◽  
Coumarin 1 ◽  
Higher Sensitivity

The performance of a series of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile derivatives as fluorescent molecular sensors for monitoring photopolymerization processes of different monomers by the Fluorescence Probe Technique (FPT) was studied. It has been shown that the new derivatives are characterized by much higher sensitivity than the commercially available 7-diethylamino-4-methylcoumarin (Coumarin 1) and trans-2-(2′,5′-dimethoxyphenyl)ethenyl-2,3,4, 5,6-pentafluorobenzene (25ST) probes. It has been discovered that the 2-amino-4,6-diphenyl-pyridine-3-carbonitrile derivatives accelerate the cationic photopolymerization process initiated with diphenyliodonium photoinitiators at the wavelength where the photoinitiator alone does not work. They are particularly efficient for the photoinitiation of cationic photopolymerization of an epoxide and vinyl monomers. Consequently, the application of the 2-amino-4,6-diphenyl-pyridine-3-carbonitrile derivatives in a dual role: (a) as fluorescent sensors for monitoring the free-radical, thiol-ene and cationic polymerization progress, and (b) as long-wavelength co-initiators for diphenyliodonium salts initiators, is proposed.

UV light activation of TiO2 for sensing formaldehyde: How to be sensitive, recovering fast, and humidity less sensitive

2014 ◽  
Vol 202 ◽  
pp. 964-970 ◽  
Author(s):  
Shunping Zhang ◽  
Tao Lei ◽  
Dong Li ◽  
Guozhu Zhang ◽  
Changsheng Xie
Keyword(s):  
Uv Light ◽  
Light Activation

scholarly journals NIR Sensitizer Operating under Long Wavelength (1064 nm) for Free Radical Photopolymerization Processes

2020 ◽  
Vol 41 (15) ◽  
pp. 2000289
Author(s):  
Haifaa Mokbel ◽  
Bernadette Graff ◽  
Frédéric Dumur ◽  
Jacques Lalevée
Keyword(s):  
Free Radical ◽  
Long Wavelength ◽  
Free Radical Photopolymerization

Practical infra-red illumination and observation techniques for wildlife studies using ICI-962 perspex

2003 ◽  
Vol 25 (2) ◽  
pp. 201 ◽  
Author(s):  
C Marks ◽  
F Busana ◽  
F Gigliotti ◽  
M Lindeman
Keyword(s):  
Uv Light ◽  
Ultra Violet ◽  
Ir Radiation ◽  
Long Wavelength ◽  
Non Invasive ◽  
Radiation Sources ◽  
Infra Red ◽  
Invaluable Tool ◽  
Free Ranging ◽  
Wavelength Light

MAMMALS do not normally visually perceive infrared (IR) or ultra-violet (UV) light that exists on either side of the visual spectrum from 390 to 760 nanometers (nm) (Wolken 1975). There is no evidence to suggest that nocturnal mammals have become more sensitive to long wavelength light as an adaptive response (Lythgoe 1979), although some reptiles can sense longer wavelength, thermal IR radiation (Barrett et al. 1970). Because it is not perceived, and is unlikely to affect animal behaviour, IR observation can be an invaluable tool for wildlife researchers. This paper describes the construction and use of simple IR radiation sources that can be used for non-invasive behavioural observations of captive and free-ranging mammals.

scholarly journals Visible-Light-Excited Room Temperature Phosphorescent Carbon Dots

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 464 ◽  
Author(s):  
Sizhe Hu ◽  
Kai Jiang ◽  
Yuci Wang ◽  
Sui Wang ◽  
Zhongjun Li ◽  
...  
Keyword(s):  
Solid State ◽  
Visible Light ◽  
Carbon Dots ◽  
Short Wavelength ◽  
Room Temperature ◽  
Uv Light ◽  
Long Wavelength ◽  
Heating Treatment ◽  
First Time ◽  
Matrix Free

Carbon dots (CDs) with a room temperature phosphorescent (RTP) feature have attracted considerable interest in recent years due to their fundamental importance and promising applications. However, the reported matrix-free RTP CDs only show short-wavelength (green to yellow) emissions and have to be triggered by ultraviolet (UV) light (below 400 nm), limiting their applications in certain fields. Herein, visible-light-excited matrix-free RTP CDs (named AA-CDs) with a long-wavelength (orange) emission are reported for the first time. The AA-CDs can be facilely prepared via a microwave heating treatment of L-aspartic acid (AA) in the presence of ammonia and they emit unique orange RTP in the solid state with visible light (420 nm) excitation just being switched off. Through the studies of the carbonization process, the C=O and C=N containing moieties in the AA-CDs are confirmed to be responsible for the observed RTP emission. Finally, the applications of AA-CDs in information encryption and anti-counterfeiting were preliminarily demonstrated.

scholarly journals New Additive for Culture Media for Rapid Identification of Aflatoxin-ProducingAspergillus Strains

2001 ◽  
Vol 67 (10) ◽  
pp. 4858-4862 ◽  
Author(s):  
C. A. Fente ◽  
J. Jaimez Ordaz ◽  
B. I. Vázquez ◽  
C. M. Franco ◽  
A. Cepeda
Keyword(s):  
Culture Media ◽  
Uv Light ◽  
Rapid Identification ◽  
Fungal Culture ◽  
Simple Method ◽  
Long Wavelength ◽  
Cyclodextrin Derivative ◽  
Natural Fluorescence ◽  
Green Fluorescent ◽  
Bright Blue

ABSTRACT A new reliable, fast, and simple method for the detection of aflatoxigenic Aspergillus strains, consisting of the addition of a cyclodextrin (a methylated β-cyclodextrin derivative) to common media used for testing mycotoxin production ability, was developed. We propose the use of this compound as an additive for fungal culture media to enhance the natural fluorescence of aflatoxins. The production of aflatoxins coincided with the presence of a bright blue or blue-green fluorescent area surrounding colonies when observed under long-wavelength (365-nm) UV light after 3 days of incubation at 28°C. The presence of aflatoxins was confirmed by extracting the medium with chloroform and examining the extracts by high-pressure liquid chromatography with fluorescence detection.

Study on Shrinkage of Cured Volume for UV-Curing Coatings

2015 ◽  
Vol 731 ◽  
pp. 588-592 ◽  
Author(s):  
Qing Kai Wang ◽  
Bei Qing Huang ◽  
Xian Fu Wei ◽  
Hao Chen Shen
Keyword(s):  
Free Radical ◽  
Uv Light ◽  
Uv Curing ◽  
Volume Shrinkage ◽  
Curing Temperature ◽  
Shrinkage Rate ◽  
Uv Curable ◽  
Cationic Resin ◽  
Polyester Acrylate ◽  
Radical Type

UV-Curable Coatings, Have been Widely Used in Machinery, Chemical Engineering, Biology, Medicine, Electronics and so on, due to their Fast Curing, Low Curing Temperature, Low VOC Emissions and Low Energy Cost. however, the Volume Shrinkage during the Curing Process Have a Great Influence on the Performance of the Coating, which Ofen Lowering Coating Adhesive Strength and Accelerating the Aging Process of Coatings Film.The Paper Select Different Kinds of Monomers (EOEOEA, HDDA, TPGDA, NPGDA, TMPTA and EO3- TMPTA) and Light Cured Resin (free Radical Type: Polyester Acrylate Resin 5600, Polyurethane Acrylate UA VP 2396, the Pure Acrylic 6536-1,cationic Resin: Epoxy Cationic Resin Omnilance OC3005) to Prepare the UV Curing Coatings. Study on the Influence of Amount of Monomer and Polymer on Polyreaction Reaction by Using Orthogonal Experimental Design Method in Order to Choose the Monomer and Polymer that has the Least Volume Shrinkage Rate, then Develop Photocureable Coating Based on Free Radical Type and Cationic Resin above. the Results Indicate that the UV-Light Photocureable Coating Prepared by Single Functionality Monomer EOEOEA and the DPGDA that Doesn’t Have Neat Molecular Structure has the Less Volume Shrinkage Rate; however, in the Aspect of Prepolymer, the Preparation of UV-Light Photocureable Coating Based on Polyester Acrylate 5600 has the Least Volume Shrinkage Rate. Rely on the Experiment Results above, Prepare the New Kind of UV-Light Photocureable Coating that has Little Volume Shrinkage Rate.

UV light-induced free radical formation in skin: An EPR study

1993 ◽  
Vol 15 (5) ◽  
pp. 528 ◽  
Author(s):  
Beth Anne Jurkiewicz ◽  
Garry R. Buettner
Keyword(s):  
Free Radical ◽  
Uv Light ◽  
Radical Formation ◽  
Free Radical Formation

scholarly journals Naphthoxy Bounded Ferrocenium Salts as Cationic Photoinitiators for Epoxy Photopolymerization

2009 ◽  
Vol 2009 ◽  
pp. 1-6
Author(s):  
Zh. Q. Li ◽  
M. Li ◽  
G. L. Li ◽  
Y. Chen ◽  
X. N. Wang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Infrared Spectroscopy ◽  
Cationic Polymerization ◽  
Uv Light ◽  
Good Thermal Stability ◽  
Long Wavelength ◽  
Dsc Studies ◽  
Arene Ligands ◽  
Epoxy Monomer ◽  
Rate Of Polymerization

To improve the absorption and the bulk of arene ligands, two naphthoxy bounded ferrocenium salts as new cationic photoinitiators, (η6-α-naphthoxybenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (NOFC-1) and (η6-β-naphthoxybenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (NOFC-2), were synthesized, characterized, and studied. NOFC-1 and NOFC-2 were prepared by the reaction of nucleophilic substitution (SNAr) with naphthol and chlorobenzene-cyclopentadienyliron salt. Their activity as cationic photoinitiators was studied using real-time infrared spectroscopy. The results obtained showed that NOFC-1 and NOFC-2 are capable of photoinitiating the cationic polymerization of epoxy monomer directly on irradiation with long-wavelength UV light (365 nm). Comparative studies also demonstrated that they exhibited better efficiency than cyclopentadienyl-Fe-cymene hexafluorophosphate (I-261). When NOFC-1 and NOFC-2 were used to efficiently initiate polymerization of epoxide, both rate of polymerization and final conversion increased using benzoyl peroxide (BPO) as sensitizer. DSC studies showed that NOFC-1 and NOFC-2 photoinitiators in epoxides possess good thermal stability in the absence of light.

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