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https://www.readbyqxmd.com/read/28441470/al2o3-and-sio2-atomic-layer-deposition-layers-on-zno-photoanodes-and-degradation-mechanisms
#1
Qian Cheng, Manpuneet Kaur Benipal, Qianlang Liu, Xingye Wang, Peter A A Crozier, Candace K Chan, Robert J Nemanich
Strategies for protecting unstable semiconductors include the utilization of surface layers comprised of thin films deposited using atomic layer deposition (ALD). The protective layer is expected to: (1) be stable against reaction with photogenerated holes, (2) prevent direct contact of the unstable semiconductor with the electrolyte, and (3) prevent the migration of ions through the semiconductor/electrolyte interface, while still allowing photogenerated carriers to transport to the interface and participate in the desired redox reactions...
April 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28440636/probing-and-comparing-the-photobromination-and-photoiodination-of-dissolved-organic-matter-by-using-ultrahigh-resolution-mass-spectrometry
#2
Zhineng Hao, Yongguang Yin, Dong Cao, Jing-Fu Liu
Photochemical halogenation of dissolved organic matter (DOM) may represent an important abiotic source of natural organobromine compounds (OBCs) and natural organoiodine compounds (OICs) within surface waters. Here we report the significantly enhanced formation of OBCs and OICs by photohalogenating DOM in freshwater and seawater, as well as the noticeable difference in distribution and composition pattern of newly formed OBCs and OICs. By using the negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, numerous OBCs and OICs were identified during the photo halogenation processes in sunlit waters...
April 25, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28437894/effect-of-anisotropic-electron-momentum-distribution-of-surface-plasmon-on-internal-photoemission-of-a-schottky-hot-carrier-device
#3
Xin-Hao Li, Jeffrey B Chou, Wei Lek Kwan, Asma M Elsharif, Sang-Gook Kim
We recently reported that an Au/TiO<sub>2</sub> photonic crystal device for photochemical energy conversion showed a sub-bandgap photoresponse centered at the surface plasmon polariton (SPP) resonant wavelength of this device. Here we developed a theoretical modeling of the internal photoemission in this device by incorporating the effects of anisotropic hot electron momentum distribution caused by SPP. The influences of interband and intraband transition, anisotropic momentum distribution of hot electrons by SPP are integrated to model the internal quantum efficiency (IQE) of this device...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28436822/distinguishing-homogeneous-heterogeneous-degradation-of-norfloxacin-in-a-photochemical-fenton-like-system-fe3o4-uv-oxalate-and-the-interfacial-reaction-mechanism
#4
Mingjie Huang, Tao Zhou, Xiaohui Wu, Juan Mao
This study demonstrated the efficient degradation of a typical bio-refractory antibiotic norfloxacin (NOR) in a photochemical iron oxides/oxalate system adopting magnetic catalyst (Fe3O4/UV/Ox). It was found that the in-situ generated HO was the main reactive oxygen species (ROS) but CO2(-) could also participate in the NOR degradation to form formylate organic intermediates. Besides, NOR would be degraded via an interesting pathway comprising an initial lag and a subsequent rapid period, where the former could be eliminated by introducing the pre-dissolution of Fe3O4 particles...
March 6, 2017: Water Research
https://www.readbyqxmd.com/read/28436526/structural-implications-on-the-excitation-dynamics-of-fluorescent-3h-indolium-cations
#5
Ek Raj Thapaliya, Jaume Garcia-Amorós, Santi Nonell, Burjor Captain, Françisco M Raymo
Fluorescent 3H-indolium cations are valuable components for the realization of activatable fluorophores for bioimaging applications. Their relatively poor fluorescent quantum yields in organic solvents, however, appear to be in contradiction to their good performance in analytical methods based on single-molecule detection. The elucidation of the structural factors governing the excitation dynamics of these compounds is, therefore, essential to rationalize these effects and possibly guide the future design of activatable probes with improved performance...
April 24, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28435255/recent-developments-in-the-nanostructured-materials-functionalized-with-ruthenium-complexes-for-targeted-drug-delivery-to-tumors
#6
REVIEW
Prakash Thangavel, Buddolla Viswanath, Sanghyo Kim
In recent years, the field of metal-based drugs has been dominated by other existing precious metal drugs, and many researchers have focused their attention on the synthesis of various ruthenium (Ru) complexes due to their potential medical and pharmaceutical applications. The beneficial properties of Ru, which make it a highly promising therapeutic agent, include its variable oxidation states, low toxicity, high selectivity for diseased cells, ligand exchange properties, and the ability to mimic iron binding to biomolecules...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28432968/applicability-of-light-sources-and-the-inner-filter-effect-in-uv-acetylacetone-and-uv-h2o2-processes
#7
Bingdang Wu, Minghui Yang, Ran Yin, Shujuan Zhang
Light source is a crucial factor in the application of a photochemical process, which determines the energy efficiency. The performances of acetylacetone (AA) in conversion of aqueous contaminants under irradiation with a low-pressure mercury lamp, a medium-pressure mercury lamp, a xenon lamp, and natural sunlight were investigated and compared with those of H2O2 as reference. In all cases, AA was superior to H2O2 in the degradation of Acid Orange 7. Using combinations of the different light sources with various cut-off and band-pass filters, the spectra responses of the absorbed photons in the UV/AA and UV/H2O2 processes were determined for two colored and two colorless compounds...
April 10, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28432906/hydrophobic-and-hydrophilic-properties-of-pollutants-as-a-factor-influencing-their-redistribution-during-snowpack-melt
#8
Krystyna Kozioł, Katarzyna Kozak, Żaneta Polkowska
Glaciers accumulate organic pollutants delivered by snow. However, our understanding of the exact dynamics of organic pollutants in the snowpack relies primarily on laboratory experiments and mathematical models. To fill the gap related to the detailed field data, we have conducted observations of melting snow profiles in two locations and three different stages of melting on one High Arctic glacier, as well as in superimposed ice. We monitored the chemical concentrations of formaldehyde, phenols, short-chain carboxylic acids, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) and snow water equivalents to derive chemical loads...
April 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28432821/addition-of-hydrogen-peroxide-to-groundwater-with-natural-iron-induces-water-disinfection-by-photo-fenton-at-circumneutral-ph-and-other-photochemical-events
#9
Héctor Mario Gutiérrez-Zapata, John Jairo Alvear-Daza, Julián Andrés Rengifo-Herrera, Janeth Sanabria
Samples of natural groundwater (with low turbidity, neutral pH and 0.3 mg L(-1) iron concentration) inoculated with Escherichia coli K-12, were exposed to simulated solar light both in the presence and absence 10 mg L(-1) of H2 O2. Results demonstrated that the viability of E. coli (by DVC-FISH) was grounded to zero after 360 min of irradiation. This abatement could be caused by the oxidative stress induced by •OH radicals or another photo-induced reactive oxygen species. Two 2(3) factorial experimental designs enabled the evaluation of the effects of chemical factors on the inactivation of E...
April 22, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28432538/superoxide-generated-in-the-chloroplast-stroma-causes-photoinhibition-of-photosystem-i-in-the-shade-establishing-tree-species-psychotria-henryi
#10
Wei Huang, Ying-Jie Yang, Jiao-Lin Zhang, Hong Hu, Shi-Bao Zhang
Our previous studies indicated that high light induced significant photoinhibition of photosystem I (PSI) in the shade-establishing tree species Psychotria henryi. However, the underlying mechanism has not been fully clarified. In the present study, in order to investigate the mechanism of PSI photoinhibition in P. henryi, we treated detached leaves with constant high light in the presence of methyl viologen (MV) or a soluble α-tocopherol analog, 2,2,5,7,8-pentamethyl-6-chromanol (PMC). We found that MV significantly depressed photochemical quantum yields in PSI and PSII when compared to PMC...
April 21, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28432320/formation-of-cuo-nano-flowered-surfaces-via-submerged-photo-synthesis-of-crystallites-and-their-antimicrobial-activity
#11
Fumika Nishino, Melbert Jeem, Lihua Zhang, Kazumasa Okamoto, Satoshi Okabe, Seiichi Watanabe
We report the fabrication of flower-like CuO nanostructured surfaces via submerged photo-synthesis of crystallites (SPSC), which requires only UV illumination in neutral water. In this paper, we discuss the reaction mechanism of the photochemical formation of the SPSC-fabricated CuO nanostructures in detail based on surface microstructural analyses and a radiation-chemical consideration with additional gamma-ray irradiation. Since the SPSC method for surface nanostructural fabrication can work at low temperatures at atmospheric pressure without using harmful substances, it is a potential fabrication method for green nanotechnology applications...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432258/lil3-a-light-harvesting-complex-protein-links-terpenoid-and-tetrapyrrole-biosynthesis
#12
Daniel Hey, Maxi Rothbart, Josephine Herbst, Peng Wang, Jakob Müller, Daniel Wittmann, Kirsten Gruhl, Bernhard Grimm
LIL3 of Arabidopsis thaliana belongs to the light-harvesting complex (LHC) family, which also includes the light-harvesting chlorophyll-binding proteins of photosystems 1 and 2, the early-light-inducible proteins, PsbS involved in non-photochemical quenching, the one-helix-proteins and their cyanobacterial homologs designated high-light-inducible proteins. Each member of this family is characterized by one or two LHC transmembrane domains (referred to as the LHC motif) to which potential functions such as chlorophyll binding, protein interaction and integration of interacting partners into the plastid membranes have been attributed...
April 21, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28431433/experimental-anterior-ischemic-optic-neuropathy-in-diabetic-mice-exhibited-severe-retinal-swelling-associated-with-vegf-elevation
#13
Ming-Hui Sun, Mohammad Ali Shariati, Yaping Joyce Liao
Purpose: Diabetes mellitus (DM) is one of the most important risk factors for nonarteritic anterior ischemic optic neuropathy (AION). In this study, we investigated for the first time the impact of experimental AION in a DM model. Methods: We induced a photochemical thrombosis model of AION after streptozotocin-induced DM and performed serial optical coherence tomography (OCT), morphometric analyses, and VEGF levels in the retina and sera. Results: Compared with non-DM animals, experimental AION in DM mice led to significantly greater retinal swelling on day 1 and worse thinning at week 3 on OCT measurements...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28431351/role-of-membrane-fouling-substances-on-the-rejection-of-n-nitrosamines-by-reverse-osmosis
#14
Takahiro Fujioka, Hitoshi Kodamatani, Hidenobu Aizawa, Stephen Gray, Kenneth P Ishida, Long D Nghiem
The impact of fouling substances on the rejection of four N-nitrosamines by a reverse osmosis (RO) membrane was evaluated by characterizing individual organic fractions in a secondary wastewater effluent and deploying a novel high-performance liquid chromatography-photochemical reaction-chemiluminescence (HPLC-PR-CL) analytical technique. The HPLC-PR-CL analytical technique allowed for a systematic examination of the correlation between the fouling level and the permeation of N-nitrosamines in the secondary wastewater effluent and synthetic wastewaters through an RO membrane...
April 3, 2017: Water Research
https://www.readbyqxmd.com/read/28430196/organocatalytic-stereoselective-8-2-and-6-4-cycloadditions
#15
Rasmus Mose, Gert Preegel, Jesper Larsen, Sofie Jakobsen, Eva Høgh Iversen, Karl Anker Jørgensen
Cycloadditions that involve more than six π electrons are termed higher-order cycloadditions and are an excellent tool for solving complex synthetic challenges, as they provide direct access to polycyclic scaffolds that contain medium-sized rings. They have interesting synthetic potential for the discovery of new bioactive molecules and in natural product synthesis. It is peculiar that stereocontrolled [8+2] and [6+4] cycloadditions have been largely neglected for the past 50 years. Here we demonstrate a cross-dienamine activation of 2-cyclopentenone and the unprecedented endocyclic linear-dienamine activation of 2-cyclohexenones and 2-cycloheptenones...
May 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28425712/synthesis-and-photooxidation-of-the-trisubstituted-oxazole-fragment-of-the-marine-natural-product-salarin-c
#16
Jan-Niklas Schäckermann, Thomas Lindel
The eastern section of the macrocyclic marine natural product salarin C from the sponge Fascaplysinopsis sp. was synthesized employing a halogen dance reaction to assemble the trisubstituted oxazole moiety. The synthesis was inspired by Kashman's hypothesis on the biomimetic oxidation of salarin C to salarin A. Clean conversion to the triacylamine partial structure of salarin A occurred on treatment with photochemically generated singlet oxygen. Thus, a Wasserman-type oxidative rearrangement is chemically possible in this case...
April 20, 2017: Organic Letters
https://www.readbyqxmd.com/read/28425538/uv-induced-hydrogen-atom-transfer-and-hydrogen-atom-detachment-in-monomeric-7-azaindole-isolated-in-ar-and-n-h2-matrices
#17
Maciej J Nowak, Igor Reva, Hanna Rostkowska, Leszek Lapinski
Photochemical transformations were investigated for monomers of 7-azaindole isolated in low-temperature Ar and normal-H2 (n-H2) matrices. The most stable N1H tautomer was the only form of the compound populated in Ar and n-H2 matrices before any irradiation. Upon exposure of Ar matrices to UV (λ > 270 nm) light, two higher-energy tautomers N7H and C3H were photoproduced. Additionally, spectral signatures of the photogenerated 7-azaindolyl radical were also found. All of these photoproducts were experimentally observed for the first time...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28424718/comparative-performance-of-multivariable-agro-physiological-parameters-for-detecting-salt-tolerance-of-wheat-cultivars-under-simulated-saline-field-growing-conditions
#18
Salah E El-Hendawy, Wael M Hassan, Nasser A Al-Suhaibani, Yahya Refay, Kamel A Abdella
Field-based trials are crucial for successfully achieving the goals of plant breeding programs aiming to screen and improve the salt tolerance of crop genotypes. In this study, simulated saline field growing conditions were designed using the subsurface water retention technique (SWRT) and three saline irrigation levels (control, 60, and 120 mM NaCl) to accurately appraise the suitability of a set of agro-physiological parameters including shoot biomass, grain yield, leaf water relations, gas exchange, chlorophyll fluorescence, and ion accumulation as screening criteria to establish the salt tolerance of the salt-tolerant (Sakha 93) and salt-sensitive (Sakha 61) wheat cultivars...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28422180/patterning-graphene-film-by-magnetic-assisted-uv-ozonation
#19
Yixuan Wu, Haihua Tao, Shubin Su, Huan Yue, Hao Li, Ziyu Zhang, Zhenhua Ni, Xianfeng Chen
Developing an alternative method for fabricating microscale graphene patterns that overcomes the obstacles of organic contamination, linewidth resolution, and substrate damaging is paramount for applications in optoelectronics. Here we propose to pattern chemical vapor deposition grown graphene film through a stencil mask by magnetic-assisted ultraviolet (UV) ozonation under irradiation of a xenon excimer lamp. In this process, the paramagnetic oxygen molecules and photochemically generated oxygen radicals are magnetized and attracted in an inhomogenous external magnetic field...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28421444/long-term-hyperthermia-impairs-activity-of-both-photosystems
#20
M A Kozuleva, E A Lysenko, A A Klaus, V V Kuznetsov
This is the first study to perform a simultaneous analysis of the activity of photosystem 1 and photosystem 2 after long-term exposure to elevated temperature. It was found that the quantum yield of photochemical reactions decreases in both photosystems. It is shown that, in photosystem 2, the regulated nonphotochemical quenching decreases whereas the unregulated non-photochemical quenching increases. In photosystem 1, limitation on both acceptor and donor sides increases.
January 2017: Doklady. Biochemistry and Biophysics
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