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Photochemical & Photobiological Sciences

Yuma Hakoda, Masatoshi Aoyagi, Ken-Ichi Irisawa, Shin-Ichiro Kato, Yosuke Nakamura, Minoru Yamaji
Phenanthrenes substituted with trimethylsilylethynyl and phenylethynyl groups were photochemically prepared, and their photophysical properties were systematically investigated based on measurements of fluorescence quantum yields, lifetimes, and transient absorption. Introducing ethynyl groups into the phenanthrene skeleton caused an increase in the fluorescence quantum yields compared to that of phenanthrene. The quantum yields and rates of fluorescence were dependent on the substituting position(s) and the terminating group for the C-C triple bond...
October 20, 2016: Photochemical & Photobiological Sciences
Ruixin Xu, Minghui He, Jianwen Yang
Benzoylformamides (BFAs) are proposed as photocaged bases for redox free radical photopolymerization (FRP). Initially the dissolving capacity of BFAs was evaluated. Besides our previously reported photo-latent anion polymerization, BFAs, as versatile photocaged bases, can not only initiate the FRP of acrylates unassisted, but also perform redox FRP in combination with a benzoyl peroxide initiator. We detail a model photopolymerization in the presence of BFA-dBA (N,N-dibenzyl-2-oxo-2-phenylacetamide) as the photocaged base...
October 18, 2016: Photochemical & Photobiological Sciences
M Á Orellana, L Osiglio, P M Arnal, L R Pizzio
Titania hollow spheres were synthesized using silica nanospheres as the template. The core was removed using NaOH solution. They were subsequently impregnated with tungstophosphoric acid (TPA) solutions and annealed at two different temperatures (100 and 500 °C). These materials were characterized by several physicochemical techniques (XRD, BET, SEM, DRS, FT-IR, FT-Raman and (31)P MAS-NMR). The (31)P MAS-NMR and FT-IR characterization showed that the main species present in the samples was the [PW12O40](3-) anion, which was partially transformed into the [P2W21O71](6-) anion during the synthesis and drying step...
October 17, 2016: Photochemical & Photobiological Sciences
Amaal Abrahams, Nicolas Mouchet, Nicolas Gouault, Françoise Lohézic Le Dévéhat, Myriam Le Roch, Isabelle Rouaud, David Gilot, Marie-Dominique Galibert
The stress-activated p38α MAP Kinase is an integral and critical component of the UV-induced inflammatory response. Despite the advances in recent years in the development of p38 kinase inhibitors, validation of these compounds in the diseased models remains limited. Based on the pharmacological profile of p38α inhibitor lead compound, SB203580, we synthesized a series of pyrrole-derivatives. Using UV-irradiated human skin punch-biopsies and cell cultures, we identified and validated the inhibitory activity of the derivatives by quantitatively measuring their effect on the expression of p38α target genes using real-time PCR...
October 17, 2016: Photochemical & Photobiological Sciences
Wen-Liang Gong, Jie Yan, Ling-Xi Zhao, Chong Li, Zhen-Li Huang, Ben Zhong Tang, Ming-Qiang Zhu
Photoswitchable fluorophores are promising in single-molecule optical devices and super-resolution fluorescence imaging, especially in single-molecule photo-activated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM). However, the scarcity of current photoswitchable fluorophores stimulates researchers to develop complicated optical systems and processing software, in accordance with the limited photoswitchable fluorescent proteins and organic fluorophores. Previous efforts to develop synthetic photoswitchable fluorophores have exhibited their promising potential in super-resolution fluorescence imaging...
October 14, 2016: Photochemical & Photobiological Sciences
Randy P Sabatini, Michael F Mark, Daniel J Mark, Mark W Kryman, Jacqueline E Hill, William W Brennessel, Michael R Detty, Richard Eisenberg, David W McCamant
Although rhodamine dyes have been extensively studied for a variety of applications, many details of their photophysics are not yet fully understood, including the possible presence of a charge separated electronic state lying near the optically active excited singlet state and the role of twisting substituent groups in excited-state quenching. To address this, a large library of rhodamine dyes was studied in which the chalcogen is varied from O, to S and Se and the aryl group is either absent (in the pyronin series) or is a phenyl or thienyl substituent...
October 13, 2016: Photochemical & Photobiological Sciences
Kara M Harmatys, Anthony J Musso, Kasey J Clear, Bradley D Smith
Administration of exogenous 5-aminolevulinic acid (5-ALA) to cancerous tissue leads to intracellular production of photoactive protoporphyrin IX, a biosynthetic process that enables photodynamic therapy and fluorescence-guided surgery of cancer. Cell uptake of 5-ALA is limited by its polar structure and there is a need for non-toxic chemical additives that can enhance its cell permeation. Two zinc-bis(dipicolylamine) (ZnBDPA) compounds were evaluated for their ability to promote uptake of 5-ALA into Chinese Hamster Ovary (CHO-K1) cells and produce protoporphyrin IX...
October 7, 2016: Photochemical & Photobiological Sciences
R Peters, L Sandiford, D M Owen, E Kemal, S Bourke, L A Dailey, M Green
Red emitting materials are desirable in biology due to the transparency of certain biological tissues at these wavelengths. Here, we report the synthesis of aqueous dispersions of amphiphilic protein (hydrophobin) capped red-emitting cyano-substituted poly(p-phenylenevinylene) conjugated polymer nanoparticles (CPNs) and their use in labeling live mammalian (HeLa) cells.
October 6, 2016: Photochemical & Photobiological Sciences
Jitendriya Swain, Ashok Kumar Mishra
The photophysical behaviour and excited state decay kinetics of the fluorescent probe Nile red were used for quantitative monitoring of micropolarity, microviscosity and the sol-gel transition temperature of a copolymer hydrogel, pluronic F127. There was considerable enhancement of the emission intensity with a large blue shift in emission and an absorption maximum at and above the sol-gel transition temperature (20 °C), showing the sensitivity of Nile red fluorescence to the sol-gel transition. The estimation of micropolarity by comparing the Nile red emission maximum in dioxane-water mixtures suggested a considerable decrease in the polarity of the PF127 microenvironment from less polar (20% dioxane-water) in its sol phase to almost non-polar (90% dioxane-water) microenvironments in the gel phase...
October 5, 2016: Photochemical & Photobiological Sciences
Hajime Maeda, Hiroki Takenaka, Kazuhiko Mizuno
With the aim of developing photoreactions that use intermolecular hydrogen bonding interactions to control the efficiency and stereochemistry, the 1,2-[2 + 2] photocycloaddition reactions of 1-cyanonaphthalene derivatives with vinyl ethers possessing hydroxy groups were examined. The photoreaction of 1-cyano-4-(hydroxymethyl)naphthalene (1a) with 2-hydroxyethyl vinyl ether (2a) at room temperature was found to produce cycloadducts, endo-3aa and exo-3aa, in a non-stereoselective manner (56 : 44). However, this photoreaction at -40 °C displays a high endo-selectivity (81 : 19)...
October 3, 2016: Photochemical & Photobiological Sciences
Vladimir A Kuzmin, Tatiana D Nekipelova, Tatyana A Podrugina, Galina V Golovina, Alexey A Kostyukov, Viktor V Temnov, Irina A Doroshenko, Eugene V Radchenko, Vladimir A Palyulin, Nikolay S Zefirov
The spectral characteristics, binding constants with bovine (BSA) and human serum albumin (HSA) and lifetimes of fluorescence in PBS and EtOH solutions and in the presence of BSA in PBS were measured for novel indotricarbocyanine dyes bearing remote phosphonate groups. These parameters are close to those for indocyanine green (ICG) indicating that the Coulomb interaction does not play a significant role in complex formation, and the binding is determined by the interaction of the dye polymethine chain with albumin...
October 3, 2016: Photochemical & Photobiological Sciences
Jianxi Wang, Cheng Zhou, Wei Liu, Jianjian Zhang, Xinyue Zhu, Xiaoyan Liu, Qin Wang, Haixia Zhang
We have prepared a near-infrared (NIR) turn-on fluorescent probe (NFC) based on chloroacetate modified naphthofluorescein for specific detection of cysteine (Cys) and homocysteine (Hcy) over glutathione (GSH) and other amino acids (AAs) with the detection limits of 0.30 μM and 0.42 μM, respectively. The fluorescence intensity of the naphthofluorescein (NF) chromophore is modulated by an internal charge transfer (ICT) process. The probe NFC is readily available and weakly fluorescent, but of observably enhanced fluorescence after reacting with Cys or Hcy...
October 3, 2016: Photochemical & Photobiological Sciences
Rui Shi, Xiaoqi Lin, Jingxuan Zhang, Hongtao Jin, Aiping Wang, Jinfeng Wei
Photodynamic therapy (PDT) is a promising antineoplastic modality in the oncology field. We assessed the safety of repeated intravenous administrations of sinoporphyrin, a porphyrin derivative, with and without illumination in rats. Toxicokinetic studies of single and multiple administrations of sinoporphyrin were also carried out. Sprague-Dawley rats were randomly assigned to the dark-toxicity and PDT groups. Animals in the dark toxicity group received an i.v. infusion of sinoporphyrin at 3 doses: 2 mg kg(-1), 6 mg kg(-1), and 18 mg kg(-1)...
September 30, 2016: Photochemical & Photobiological Sciences
Zafar Mahmood, Jianzhang Zhao
Fluorescent molecular probes based on photo-induced electron transfer (PET) are well-known for which fluorescence is efficiently tuned OFF/ON by a PET process. Now we demonstrate that the triplet excited state of the probes is unable to be quenched by PET, which is in stark contrast to the singlet excited state (fluorescence). This conclusion was proved by the preparation of a fluorescent molecular probe BDP-DPA, which shows enhanced fluorescence upon addition of a Zn(ii) salt. With fluorescence spectroscopy, nanosecond transient absorption spectroscopy and electrochemical studies, we found that the triplet excited state of BDP-DPA was not quenched by any PET process, although the singlet excited state (fluorescence) of BDP-DPA was quenched...
September 29, 2016: Photochemical & Photobiological Sciences
S García Ballesteros, M Costante, R Vicente, M Mora, A M Amat, A Arques, L Carlos, F S García Einschlag
In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insight into the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organic substances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis (PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBO solutions studied...
September 29, 2016: Photochemical & Photobiological Sciences
Firas H Abdulrazzak, Falah H Hussein, Ayad F Alkaim, Irina Ivanova, Alexei V Emeline, Detlef W Bahnemann
Modified Pt-TiO2 NPs/decorated carbon nanotubes were synthesized utilizing sonochemical/hydration-dehydration techniques. Pt was loaded on TiO2 by a photodeposition method keeping in mind the end goal to achieve electron-hole pair separation and promote the surface reaction. The morphological and basic properties of Pt-TiO2/fCNTs were investigated by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and Raman spectroscopy...
September 28, 2016: Photochemical & Photobiological Sciences
J F Góngora, P Elizondo, A Hernández-Ramírez
In this work, modification of TiO2 was carried out by incorporation of two novel Ru(ii) polyaza complexes. The N(1)-(2-aminobenzyliden)-N(2),N(2)-bis(2-(2-aminobenzyliden)aminoethyl)ethane-1,2-diaminoruthenium(ii) and N(1),N(2)-bis(2-aminobenziliden)ethane-1,2-diaminoruthenium(ii) complexes were synthesized via metal-ligand direct reaction. The complexes were characterized by UV-Vis, FTIR and fluorescence spectroscopy, and the chemical composition was obtained from elemental analysis by the combustion method; additionally, the sensitized TiO2 catalysts were also characterized by XRD, SEM and diffuse reflectance techniques...
September 21, 2016: Photochemical & Photobiological Sciences
Mohamed E El-Khouly, Shunichi Fukuzumi
We reported herein the spectroscopic, electrochemical and laser photolysis studies for the newly constructed light harvesting supramolecular dyad composed of gold porphyrin (AuPpy), as an electron acceptor, and zinc phthalocyanine (ZnPc), as an electron donor, to mimic the reaction centre in the photosynthetic system. For this, gold porphyrin has been functionalized by pyridine units, which axially coordinated with zinc phthalocyanine to form the stable supramolecular AuPpy:ZnPc with a rate of 2.94 × 10(4) M(-1)...
September 9, 2016: Photochemical & Photobiological Sciences
N C Birben, M C Paganini, P Calza, M Bekbolet
This study aimed at investigating the photocatalytic degradation of humic acid (HA) as a representative of natural organic matter (NOM) by using Ce-doped ZnO as a novel material. Following photocatalysis, HA degradation was characterized by specified UV-vis and fluorescence spectroscopic parameters as well as by the dissolved organic carbon (NPOC) content. Excitation-Emission Matrix (EEM) fluorescence features were also evaluated by using advanced techniques. Comparison of Ce-doped ZnO photocatalysis to TiO2 P-25 photocatalytic treatment of the HA samples was elucidated under similar experimental conditions...
September 8, 2016: Photochemical & Photobiological Sciences
Stephanie Bora, Margherita T Cantorna
Vitamin D deficiency is associated with the development of inflammatory bowel disease (IBD). In experimental IBD the targets of vitamin D that result in protection from IBD include gut epithelial cells, innate immune cells, T cells, and the microbiota. Ultraviolet radiation (UVR) induces production of vitamin D in the skin and suppresses T cell responses in the host. There is limited data demonstrating an effect of UVR on experimental IBD but the mechanisms of UVR suppression in IBD have not been defined. There are several shared effects of vitamin D and UVR on T cells including inhibition of proliferation and suppression of IFN-γ and IL-17 producing T cells...
September 8, 2016: Photochemical & Photobiological Sciences
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