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Photo sensitivity

Yonghe Tang, Yanyan Ma, An Xu, Gaoping Xu, Weiying Lin
As the simplest aldehyde compounds, formaldehyde (FA) is implicated in nervous system diseases and cancer. Endoplasmic reticulum is an organelle that plays important functions in living cells. Accordingly, the development of efficient methods for FA detection in the endoplasmic reticulum (ER) is of great biomedical importance. In this work, we developed the first ER-targeted fluorescent FA probe Na-FA-ER. The detection is based on the condensation reaction of the hydrazine group and FA to suppress the photo-induced electron transfer (PET) pathway, resulting in a fluorescence increase...
April 21, 2017: Methods and Applications in Fluorescence
Steven D Schwartzbach
Euglena can use light and CO2, photosynthesis, as well as a large variety of organic molecules as the sole source of carbon and energy for growth. Light induces the enzymes, in this case an entire organelle, the chloroplast, that is required to use CO2 as the sole source of carbon and energy for growth. Ethanol, but not malate, inhibits the photoinduction of chloroplast enzymes and induces the synthesis of the glyoxylate cycle enzymes that comprise the unique metabolic pathway leading to two carbon, ethanol and acetate, assimilation...
2017: Advances in Experimental Medicine and Biology
Gabriel Biener, Daniela S Masson-Meyers, Violet V Bumah, Grant Hussey, Michael R Stoneman, Chukuka S Enwemeka, Valerica Raicu
The resistance of methicillin-resistant Staphylococcus aureus to antibiotics presents serious clinical problems that prompted the need for finding alternative or combination therapies. One such therapy is irradiation with blue light. To determine the alterations in metabolic processes implicated in the observed antimicrobial effects of blue light, we investigated the changes in membrane potential and the presence of free-radical-producing photo-acceptor molecules. Bacterial cultures irradiated with one or two doses of 405nm laser light (each consisting of 121J/cm(2)) were imaged with spectrally resolved laser-scanning microscopes to detect endogenous fluorescent species as well as the voltage sensitive dye 3,3'-Diethyloxacarbocyanine iodide...
April 6, 2017: Journal of Photochemistry and Photobiology. B, Biology
Xiaoqian Zhang, Qi Zhao, Yanru Li, Xinrui Duan, Yanli Tang
Nitroreductase (NTR) is overexpressed in hypoxic tumors. Moreover, hypoxia is usually considered as a most important feature of various diseases. Thus it is important to build a sensitive and selective method for NTR detection and hypoxia diagnosis. Herein, a new cationic conjugated polymer (PBFBT-NP) with p-nitrophenyl group in the side chain was designed and synthesized as a fluorescent probe for the detection of NTR. In the absence of NTR, the fluorescence of PBFBT-NP was quenched due to photo-induced electron transfer (PET)...
April 19, 2017: Analytical Chemistry
Katia Mattarozzi, Valentina Colonnello, Francesco De Gioia, Alexander Todorov
PURPOSE: Prior research has demonstrated that healthcare providers' implicit biases may contribute to healthcare disparities. Independent research in social psychology indicates that facial appearance-based evaluations affect social behavior in a variety of domains, influencing political, legal, and economic decisions. Whether and to what extent these evaluations influence approach behavior in healthcare contexts warrants research attention. Here we investigate the impact of facial appearance-based evaluations of trustworthiness on healthcare providers' caring inclination, and the moderating role of experience and information about the social identity of the faces...
April 12, 2017: Social Science & Medicine
William White, Christopher D Sanborn, Ronald S Reiter, David M Fabian, Shane Ardo
Replacing passive ion-exchange membranes, like Nafion, with membranes that use light to drive ion transport would allow membranes in photoelectrochemical technologies to serve in an active role. Toward this, we modified per-fluorosulfonic acid ionomer membranes with organic pyrenol-based photoacid dyes to sensitize the membranes to visi-ble light and initiate proton transport. Covalent modification of the membranes was achieved by reacting Nafion sul-fonyl fluoride poly(perfluorosulfonyl fluoride) membranes with 8-hydroxypyrene-1,3,6-tris(2-aminoethylsulfonamide) photoacids...
April 17, 2017: Journal of the American Chemical Society
Nader Shokoufi, Atefeh Abbasi-Ahd, Kazem Kargosha
In this work, a combined flow injection-photo thermal lens microscopy (FI-PTLM) system was used for highly sensitive determination of captopril as an angiotensin-converting enzyme inhibitor. Captopril has no absorption in the visible range, but due to its thiol group could interact with gold nanoparticles (GNPs). GNPs, because of their surface plasmon resonance (SPR), have absorption in the visible range, but their interaction with a low concentration of captopril shows no effective change in UV-Vis spectrophotometry because their aggregation is slight...
April 10, 2017: Applied Optics
Mazhar Chebl, Zeinab Moussa, Markus Peurla, Digambara Patra
As a proof of concept, here it is established that curcumin integrated chitosan oligosaccharide lactate (COL) self-assembles on silica nanoparticle surface to form nano hybrid particles (NHPs). These NHPs have size in the ranges of 25-35nm with silica nanoparticle as its core and curcumin-COL as outer layer having thickness of 4-8nm. The fluorescence intensity of these NHPs are found to be quenched and emission maximum is ~50nm red shifted compared to free curcumin implying inner filter effect and/or homo-FRET between curcumin molecules present on the surface of individual nano hybrid particle...
July 1, 2017: Talanta
Dan Wu, Xukai Li, Yiming Tang, Ping Lu, Weirui Chen, Xiaoting Xu, Laisheng Li
Zinc oxide (ZnO) nanorods were prepared by a directly pyrolysis method and employed as catalyst for perfluorooctanoic acid (PFOA) degradation. Comparative experiments were conducted to discuss the catalytic activity and flexibility of ZnO. After ZnO addition, the best PFOA degradation efficiency (70.5%) was achieved by ZnO/UV/O3 system, only 9.5% by sole ozonation and 18.2% by UV254 light irradiation. PFOA degradation was sensitive with pH value and temperature. The better PFOA removal efficiency was achieved at acidic condition...
April 3, 2017: Chemosphere
Kanji Okumoto, Yukio Fujiki
Cell mutants with a genetic defect affecting various cellular phenotypes are widely utilized as a powerful tool in genetic, biochemical, and cell biological research. More than a dozen complementation groups of animal somatic mutant cells defective in peroxisome biogenesis have been successfully isolated in Chinese hamster ovary (CHO) cells and used as a model system reflecting fatal human severe genetic disorders named peroxisome biogenesis disorders (PBD). Isolation and characterization of peroxisome-deficient CHO cell mutants has allowed the identification of PEX genes and the gene products peroxins, which directly leads to the accomplishment of isolation of pathogenic genes responsible for human PBDs, as well as elucidation of their functional roles in peroxisome biogenesis...
2017: Methods in Molecular Biology
Sumit Kumar Pramanik, Patricia Losada-Pe Rez, Gunter Reekmans, Robert Carleer, Marc D'Olieslaeger, Dirk Vanderzande, Peter Adriaensens, Anitha Ethirajan
With recent advances in the field of diagnostics and theranostics, liposomal technology has secured a fortified position as a potential nanocarrier. Specifically, radiation/photo-sensitive liposomes containing photo-polymerizable cross-linking lipids are intriguing as they can impart the vesicles with highly interesting properties such as response to stimulus and improved shell stability. In this work, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine (DTPE) is used as a photo-polymerizable lipid to form functional hybrid-liposomes as it can form intermolecular cross-linking through the diacetylenic groups...
April 13, 2017: Scientific Reports
John H Stockley, Kimberley Evans, Moritz Matthey, Katrin Volbracht, Sylvia Agathou, Jana Mukanowa, Juan Burrone, Ragnhildur T Káradóttir
Light is extensively used to study cells in real time (live cell imaging), separate cells using fluorescence activated cell sorting (FACS) and control cellular functions with light sensitive proteins (Optogenetics). However, photo-sensitive molecules inside cells and in standard cell culture media generate toxic by-products that interfere with cellular functions and cell viability when exposed to light. Here we show that primary cells from the rat central nervous system respond differently to photo-toxicity, in that astrocytes and microglia undergo morphological changes, while in developing neurons and oligodendrocyte progenitor cells (OPCs) it induces cellular death...
April 12, 2017: Scientific Reports
Peiqi Zhou, Zhikai Gan, Xu Huang, Chunlian Mei, Yuxing Xia, Hui Wang
In this article, we report a magnetic tuning lateral photovoltaic effect (LPE) in a nonmagnetic Si-based Schottky junctions. In the magnetic field intensity range of 0 to 1.6 T, the variation amplitude of LPE sensitivity is as high as 94.8%, the change of LPV is and the change rate of lateral photo-voltage even reaches 520 mV/T at 1.5 T, which is apparently higher than the results of previous reported researches in magnetic materials. This effect is attributed to the combined result of the influence of magnetic field on diffusion current and the rectification property of our anisotropic structure...
April 11, 2017: Scientific Reports
Nicklas Skjoldager, Maria Blanner Bang, Martin Rykær, Olof Björnberg, Michael J Davies, Birte Svensson, Pernille Harris, Per Hägglund
The NADPH-dependent homodimeric flavoenzyme thioredoxin reductase (TrxR) provides reducing equivalents to thioredoxin, a key regulator of various cellular redox processes. Crystal structures of photo-inactivated thioredoxin reductase (TrxR) from the Gram-positive bacterium Lactococcus lactis have been determined. These structures reveal novel molecular features that provide further insight into the mechanisms behind the sensitivity of this enzyme toward visible light. We propose that a pocket on the si-face of the isoalloxazine ring accommodates oxygen that reacts with photo-excited FAD generating superoxide and a flavin radical that oxidize the isoalloxazine ring C7α methyl group and a nearby tyrosine residue...
April 11, 2017: Scientific Reports
Andrea Paolella, Cyril Faure, Giovanni Bertoni, Sergio Marras, Abdelbast Guerfi, Ali Darwiche, Pierre Hovington, Basile Commarieu, Zhuoran Wang, Mirko Prato, Massimo Colombo, Simone Monaco, Wen Zhu, Zimin Feng, Ashok Vijh, Chandramohan George, George P Demopoulos, Michel Armand, Karim Zaghib
Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging...
April 10, 2017: Nature Communications
Renato Ivan de Ávila, Gabriel Campos Teixeira, Danillo Fabrini Maciel Costa Veloso, Larissa Cleres Moreira, Eliana Lima Martins, Marize Campos Valadares
This study evaluated the applicability of a modified Direct Peptide Reactivity Assay (DPRA) (OECD N° 442C, 2015) through the 10-fold reduction of reaction volume (micro-DPRA, mDPRA) for skin sensitization evaluation of six commercial glyphosate-containing formulations. In addition, another modification of DPRA was proposed by adding a UVA (5J/cm(2)) irradiation step, namely photo-mDPRA, to better characterize (photo)sensitizer materials. The phototoxicity profile of pesticides was also evaluated using the 3T3 Neutral Red Uptake Phototoxicity Test (3T3-NRU-PT) (OECD N° 432, 2004)...
April 4, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Ming He, Baoqin Han, Zhiwen Jiang, Yan Yang, Yanfei Peng, Wanshun Liu
Hydroxyethyl chitosan (HECTS) is one of the most important water soluble derivatives of chitosan. In this study, photo-sensitive azidehydroxyethyl chitosan (AZ-HECTS) was synthesized with grafting degree 3.4%, and its water solution resulted in an insoluble hydrogel by 254nm UV irradiation for 90s. AZ-HECTS hydrogels, with water absorption 86.21%, had little impact on growth of mouse fibroblast (L929) and presented good cell biocompatibility. Obvious sudden degradation stage, slow degradation stage and no apparent toxicity was observed after AZ-HECTS hydrogels implanted into rats, and tissue inflammation was slighter, which indicated favorable biological safety...
June 15, 2017: Carbohydrate Polymers
Weibing Yang, Yanxia Li, Yanping Yin, Zhilie Qin, Mengjing Zheng, Jin Chen, Yongli Luo, Dangwei Pang, Wenwen Jiang, Yong Li, Zhenlin Wang
Severe water deficit (SD) severely limited the photo-assimilate supply during the grain-filling stages. Although the ethylene and polyamines (PAs) have been identified as important signaling molecules involved in stress tolerance, it is yet unclear how 1-Aminocylopropane-1-carboxylic acid (ACC) and PA biosynthesis involving wheat abdominal phloem characters mitigate SD-induced filling inhibition. The results obtained indicated that the SD down-regulated the TaSUT1 expression and decreased the activities of sucrose synthase (SuSase, EC2...
April 6, 2017: Scientific Reports
Yue Wang, Lijie Zhu, Yufeng Hu, Zhenbo Deng, Zhidong Lou, Yanbing Hou, Feng Teng
Most organic photodetectors utilize a bulk heterojunction (BHJ) photo-active film due to its high exciton dissociation efficiency. However, the low dark current density, a key role in determining the overall performance of photodetectors, is hardly achieved in the BHJ structure since both the donor and acceptor domains are in contact with the same electrode. The most popular strategy to overcome this problem is by fabricating bilayer or multilayer devices. However, the complicated fabrication process is a challenge for printing electronics...
April 3, 2017: Optics Express
Yue Shi, Chenxiang Zhao, Jacob Yeuk-Lung Ho, Valery V Vashchenko, Abhishek Kumar Srivastava, Vladimir G Chigrinov, Hoi-Sing Kwok, Feng Song, Dan Luo
Azobenzene photoalignment materials are highly effective for liquid crystal alignment with high sensitivity and rewritability. A strong relationship between relative humidity and the alignment quality of a thin layer of azobenzene sulfonic dye has been investigated, where the photo-induced phase retardation, order parameter and anchoring strength of the alignment layer are influenced dramatically by relative humidity. Our results provide fabrication guidance for the photoalignment process in both display and photonic applications...
April 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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