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https://www.readbyqxmd.com/read/27916848/water-will-be-the-coal-of-the-future-the-untamed-dream-of-jules-verne-for-a-solar-fuel
#1
REVIEW
Vladimir K Ryabchuk, Vyacheslav N Kuznetsov, Alexei V Emeline, Yurii M Artem'ev, Galina V Kataeva, Satoshi Horikoshi, Nick Serpone
This article evokes the futuristic visions of two giants, one a writer, Jules Verne, who foresaw water as the coal of the future, and the other a scientist, Giacomo Ciamician, who foresaw the utilization of solar energy as an energy source with which to drive photochemical and photocatalytic reactions for the betterment of mankind. Specifically, we examine briefly the early work of the 1960s and 1970s on the photosplitting of free water and water adsorbed on solid supports, based mostly on metal oxides, from which both hydrogen and oxygen evolve in the expected stoichiometric ratio of 2 to 1...
November 29, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27914582/photochemistry-of-nanoporous-carbons-perspectives-in-energy-conversion-and-environmental-remediation
#2
REVIEW
Alicia Gomis-Berenguer, Leticia F Velasco, Inmaculada Velo-Gala, Conchi O Ania
The interest in the use of nanoporous carbon materials in applications related to energy conversion and storage, either as catalysts or additives, has grown over recent decades in various disciplines. Since the early studies reporting the benefits of the use of nanoporous carbons as inert supports of semiconductors and as electron acceptors that enhance the splitting of the photogenerated excitons, many researchers have investigated the key role of carbon matrices coupled to all types of photoactive materials...
November 16, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27905600/vuv-photochemistry-of-the-h2oco-complex-in-noble-gas-matrices-formation-of-the-ohco-complex-and-the-hoco-radical
#3
Sergey V Ryazantsev, Luís Duarte, Vladimir I Feldman, Leonid Khriachtchev
Vacuum ultraviolet (VUV, 130-170 nm) photochemistry of the H2OCO complex is studied by matrix-isolation infrared spectroscopy. The H2OCO complexes in Ne, Ar, Kr, and Xe matrices are generated by ultraviolet (UV, 193 and 250 nm) photolysis of formic acid (HCOOH). VUV photolysis of the H2OCO complexes is found to lead to the formation of the OHCO radical-molecule complexes and trans-HOCO radicals. It is shown that the matrix material, local matrix morphology, and possibly the H2OCO complex geometry strongly affect the VUV photolysis pathways...
December 1, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27898056/comparative-photochemistry-activity-and-antioxidant-responses-in-male-and-female-populus-cathayana-cuttings-inoculated-with-arbuscular-mycorrhizal-fungi-under-salt
#4
Na Wu, Zhen Li, Fei Wu, Ming Tang
We investigated the impact of arbuscular mycorrhizal fungi (AMF) on the morphology and physiology of two genders of the typical dioecious plant Populus cathayana under salt stress. We conducted a pot experiment containing seedlings of the two genders that were subjected to salt or non-salt and filled with soil that was either inoculated with Rhizophagus intraradices or not. The results showed that males had higher mycorrhizal dependency than females. Salt stress decreased growth, the relative water content and chlorophyll fluorescence...
November 29, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27896886/two-in-one-%C3%AE-orthogonal-photochemistry-on-a-radical-photoinitiating-system
#5
Silvana Hurrle, Andrea Lauer, Hartmut Gliemann, Hatice Mutlu, Christof Wöll, Anja S Goldmann, Christopher Barner-Kowollik
An alkyne functional radical photoinitiator, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl hex-5-ynoate, and evidence that both reactive moieties - the alkyne and the photoinitiator terminus - can be independently addressed with light of disparate wavelength (λ-orthogonality) are introduced. The alkyne functionality is subjected to a visible light (420 nm) induced copper-catalyzed Huisgen reaction, which is employed for the selective functionalization of the initiator with a poly(ethylene glycol) (PEG) chain...
November 29, 2016: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/27895261/photochemistry-of-framework-supported-m-diimine-co-3x-complexes-in-three-dimensional-lithium-carboxylate-metal-organic-frameworks-monitoring-the-effect-of-framework-cations
#6
Thomas J Reade, Thomas S Murphy, James A Calladine, Raphael Horvath, Ian P Clark, Gregory M Greetham, Michael Towrie, William Lewis, Michael W George, Neil R Champness
The structures and photochemical behaviour of two new metal-organic frameworks (MOFs) are reported. Reaction of Re(2,2'-bipy-5,5'-dicarboxylic acid)(CO)3Cl or Mn(2,2'-bipy-5,5'-dicarboxylic acid)(CO)3Br with LiCl or LiBr, respectively, produces single crystals of {Li2(DMF)2 [(2,2'-bipy-5,5'-dicarboxylate)Re(CO)3Cl]}n ( RELI: ) or {Li2(DMF)2[(2,2'-bipy-5,5'-dicarboxylate)Mn(CO)3Br]}n ( MNLI: ). The structures formed by the two MOFs comprise one-dimensional chains of carboxylate-bridged Li(I) cations that are cross-linked by units of Re(2,2'-bipy-5,5'-dicarboxylate)(CO)3Cl ( RELI: ) or Mn(2,2'-bipy-5,5'- dicarboxylate)(CO)3Br ( MNLI: )...
January 13, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/27890002/photosensitizers-for-photodynamic-therapy-photochemistry-in-the-service-of-oncology
#7
Carsten Lange, Patrick J Bednarski
The combined use of a photosensitizing agent, light and dioxygen for the treatment of diseases has become known as photodynamic therapy (PDT) and was first discovered more than one hundred years ago. Over the years, PDT has proven its potential for the treatment of malignant and non-malignant lesions in addition to classical cancer therapy in numerous clinical studies, but application as a routine method is still limited. In this review, the development of modern PDT since the beginning of the twentieth century is briefly portrayed...
November 24, 2016: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/27877247/beyond-the-barriers-of-light-penetration-strategies-perspectives-and-possibilities-for-photodynamic-therapy
#8
REVIEW
Srivalleesha Mallidi, Sriram Anbil, Anne-Laure Bulin, Girgis Obaid, Megumi Ichikawa, Tayyaba Hasan
Photodynamic therapy (PDT) is a photochemistry based treatment modality that involves the generation of cytotoxic species through the interactions of a photosensitizer molecule with light irradiation of an appropriate wavelength. PDT is an approved therapeutic modality for several cancers globally and in several cases has proved to be effective where traditional treatments have failed. The key parameters that determine PDT efficacy are 1. the photosensitizer (nature of the molecules, selectivity, and macroscopic and microscopic localization etc...
2016: Theranostics
https://www.readbyqxmd.com/read/27872654/chlorophyll-a-fluorescence-under-half-of-the-adaptive-growth-irradiance-for-high-throughput-sensing-of-leaf-water-deficit-in-arabidopsis-thaliana-accessions
#9
Kumud B Mishra, Anamika Mishra, Kateřina Novotná, Barbora Rapantová, Petra Hodaňová, Otmar Urban, Karel Klem
BACKGROUND: Non-invasive and high-throughput monitoring of drought in plants from its initiation to visible symptoms is essential to quest drought tolerant varieties. Among the existing methods, chlorophyll a fluorescence (ChlF) imaging has the potential to probe systematic changes in photosynthetic reactions; however, prerequisite of dark-adaptation limits its use for high-throughput screening. RESULTS: To improve the throughput monitoring of plants, we have exploited their light-adaptive strategy, and investigated possibilities of measuring ChlF transients under low ambient irradiance...
2016: Plant Methods
https://www.readbyqxmd.com/read/27871088/structure-of-photosystem-ii-and-substrate-binding-at-room-temperature
#10
Iris D Young, Mohamed Ibrahim, Ruchira Chatterjee, Sheraz Gul, Franklin D Fuller, Sergey Koroidov, Aaron S Brewster, Rosalie Tran, Roberto Alonso-Mori, Thomas Kroll, Tara Michels-Clark, Hartawan Laksmono, Raymond G Sierra, Claudiu A Stan, Rana Hussein, Miao Zhang, Lacey Douthit, Markus Kubin, Casper de Lichtenberg, Long Vo Pham, Håkan Nilsson, Mun Hon Cheah, Dmitriy Shevela, Claudio Saracini, Mackenzie A Bean, Ina Seuffert, Dimosthenis Sokaras, Tsu-Chien Weng, Ernest Pastor, Clemens Weninger, Thomas Fransson, Louise Lassalle, Philipp Bräuer, Pierre Aller, Peter T Docker, Babak Andi, Allen M Orville, James M Glownia, Silke Nelson, Marcin Sikorski, Diling Zhu, Mark S Hunter, Thomas J Lane, Andy Aquila, Jason E Koglin, Joseph Robinson, Mengning Liang, Sébastien Boutet, Artem Y Lyubimov, Monarin Uervirojnangkoorn, Nigel W Moriarty, Dorothee Liebschner, Pavel V Afonine, David G Waterman, Gwyndaf Evans, Philippe Wernet, Holger Dobbek, William I Weis, Axel T Brunger, Petrus H Zwart, Paul D Adams, Athina Zouni, Johannes Messinger, Uwe Bergmann, Nicholas K Sauter, Jan Kern, Vittal K Yachandra, Junko Yano
Light-induced oxidation of water by photosystem II (PS II) in plants, algae and cyanobacteria has generated most of the dioxygen in the atmosphere. PS II, a membrane-bound multi-subunit pigment protein complex, couples the one-electron photochemistry at the reaction centre with the four-electron redox chemistry of water oxidation at the Mn4CaO5 cluster in the oxygen-evolving complex (OEC). Under illumination, the OEC cycles through five intermediate S-states (S0 to S4), in which S1 is the dark-stable state and S3 is the last semi-stable state before O-O bond formation and O2 evolution...
November 21, 2016: Nature
https://www.readbyqxmd.com/read/27870584/follow-the-carbon-isotopic-labeling-studies-of-early-earth-aerosol
#11
Raea K Hicks, Douglas A Day, Jose L Jimenez, Margaret A Tolbert
Despite the faint young Sun, early Earth might have been kept warm by an atmosphere containing the greenhouse gases CH4 and CO2 in mixing ratios higher than those found on Earth today. Laboratory and modeling studies suggest that an atmosphere containing these trace gases could lead to the formation of organic aerosol haze due to UV photochemistry. Chemical mechanisms proposed to explain haze formation rely on CH4 as the source of carbon and treat CO2 as a source of oxygen only, but this has not previously been verified experimentally...
November 2016: Astrobiology
https://www.readbyqxmd.com/read/27866363/comparative-of-quercus-spp-and-salix-spp-for-phytoremediation-of-pb-zn-mine-tailings
#12
Xiang Shi, Shufeng Wang, Haijing Sun, Yitai Chen, Dongxue Wang, Hongwei Pan, Yazhu Zou, Jianfeng Liu, Linyu Zheng, Xiulian Zhao, Zeping Jiang
A pot experiment was conducted to evaluate the feasibility of using tree seedlings for the phytoremediation of lead/zinc (Pb/Zn) mine tailings. Seedlings of three Quercus spp. (Q. shumardii, Q. phellos, and Q. virginiana) and rooted cuttings of two Salix spp. (S. matsudana and S. integra) were transplanted into pots containing 50 and 100 % Pb/Zn mine tailings to evaluate their tolerance of heavy metals. The five species showed different tolerance levels to the Pb/Zn tailings treatments. Q. virginiana was highly tolerant to heavy metals and grew normally in the Pb/Zn tailings...
November 19, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27864175/the-acceptor-side-of-photosystem-ii-is-the-initial-target-of-nitrite-stress-in-synechocystis-sp-pcc-6803
#13
Xin Zhang, Fei Ma, Xi Zhu, Junying Zhu, Junfeng Rong, Jiao Zhan, Hui Chen, Chenliu He, Qiang Wang
: Nitrite, a common form of inorganic nitrogen (N), can be used as a nitrogen source through N assimilation. However, high levels of nitrite depress photosynthesis in various organisms. In this study, we investigated which components of the photosynthetic electron transfer chain are targeted by nitrite stress in Synechocystis sp. PCC 6803 cells. Measurements of whole-chain and PSII-mediated electron transport activities revealed that high levels of nitrite primarily impair electron flow in PSII...
November 18, 2016: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27862802/symmetry-breaking-charge-transfer-and-hydrogen-bonding-toward-asymmetrical-photochemistry
#14
Bogdan Dereka, Arnulf Rosspeintner, Maciej Krzeszewski, Daniel T Gryko, Eric Vauthey
Symmetry-breaking charge transfer upon photoexcitation of a linear A-π-D-π-A molecule (D and A being electron donating and accepting groups) could be visualized using ultrafast time-resolved infrared spectroscopy by monitoring the CN stretching modes on the A units. Whereas in apolar solvents, the S1 state remains symmetric and quadrupolar, symmetry breaking occurs within ca. 100 fs in polar solvents as shown by the presence of two CN bands, instead of one in apolar solvents, with a splitting that increases with polarity...
November 15, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27858050/novel-hetarylazo-dyes-containing-tetrazole-and-hydroquinoline-moieties-spectral-characteristics-solvatochromism-and-photochemistry
#15
Tatiana D Nekipelova, Evgenii N Khodot, Olga N Klimovich Lygo, Lidiya N Kurkovskaya, Irina I Levina, Vladimir A Kuzmin
Novel hetarylazo dyes containing tetrazole and tetra- or dihydroquinoline moieties were synthesized and their spectral properties in solvents of different polarities and H-bonding abilities were examined. The dyes exhibit solvatochromism dramatically depending on the proton accepting ability of solvents: (DMSO > H2O > MeOH > ACN > CH2Cl2) and the dye concentration. Upon dilution the absorption maximum of the visible band shows a blue shift and the absorption coefficient of the maximum decreases...
November 30, 2016: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/27854005/new-insights-into-the-photochemistry-of-carotenoid-spheroidenone-in-light-harvesting-complex-2-from-the-purple-bacterium-rhodobacter-sphaeroides
#16
Dariusz M Niedzwiedzki, Preston L Dilbeck, Qun Tang, Elizabeth C Martin, David F Bocian, C Neil Hunter, Dewey Holten
Light-harvesting complex 2 (LH2) from the semi-aerobically grown purple phototrophic bacterium Rhodobacter sphaeroides was studied using optical (static and time-resolved) and resonance Raman spectroscopies. This antenna complex comprises bacteriochlorophyll (BChl) a and the carotenoid spheroidenone, a ketolated derivative of spheroidene. The results indicate that the spheroidenone-LH2 complex contains two spectral forms of the carotenoid: (1) a minor, "blue" form with an S2 (1(1)B u(+) ) spectral origin band at 522 nm, shifted from the position in organic media simply by the high polarizability of the binding site, and (2) the major, "red" form with the origin band at 562 nm that is associated with a pool of pigments that more strongly interact with protein residues, most likely via hydrogen bonding...
November 16, 2016: Photosynthesis Research
https://www.readbyqxmd.com/read/27852123/acanthopanax-senticosus-photochemistry-and-anticancer-potential
#17
Ting Li, Kelsey Ferns, Zi-Qiao Yan, Si-Yuan Yin, Jun-Jie Kou, Dongsheng Li, Zheng Zeng, Lin Yin, Xiaoyu Wang, Hong-Xia Bao, Yu-Jie Zhou, Qing-Hai Li, Zhan-Yi Zhao, Huidi Liu, Shu-Lin Liu
Acanthopanax senticosus (previously classified as Eleutherococcus senticosus), commonly known as Ciwujia or Siberian Ginseng, is a traditional Chinese medicine (TCM), widely used for its high medicinal value, such as antifatigue, anti-inflammation, antistress, anti-ulcer and cardiovascular functions, in China, Korea, Japan and Russia. In the past decades, researchers worldwide have conducted systematic investigations on this herb, from chemistry to pharmacology, and a large number of chemical components have been characterized for their significant pharmacological effects...
November 16, 2016: American Journal of Chinese Medicine
https://www.readbyqxmd.com/read/27834931/chemistry-and-photochemistry-of-anthocyanins-and-related-compounds-a-thermodynamic-and-kinetic-approach
#18
Nuno Basílio, Fernando Pina
Anthocyanins are identified by the respective flavylium cation, which is only one species of a multistate of different molecules reversibly interconverted by external inputs such as pH, light and temperature. The flavylium cation (acidic form) is involved in an apparent acid-base reaction, where the basic species is the sum of quinoidal base, hemiketal and cis- and trans-chalcones, their relative fraction depending on the substitution pattern of the flavylium cation. The full comprehension of this complex system requires a thermodynamic and kinetic approach...
November 10, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27833145/impacts-of-brown-carbon-from-biomass-burning-on-surface-uv-and-ozone-photochemistry-in-the-amazon-basin
#19
Jungbin Mok, Nickolay A Krotkov, Antti Arola, Omar Torres, Hiren Jethva, Marcos Andrade, Gordon Labow, Thomas F Eck, Zhanqing Li, Russell R Dickerson, Georgiy L Stenchikov, Sergey Osipov, Xinrong Ren
The spectral dependence of light absorption by atmospheric particulate matter has major implications for air quality and climate forcing, but remains uncertain especially in tropical areas with extensive biomass burning. In the September-October 2007 biomass-burning season in Santa Cruz, Bolivia, we studied light absorbing (chromophoric) organic or "brown" carbon (BrC) with surface and space-based remote sensing. We found that BrC has negligible absorption at visible wavelengths, but significant absorption and strong spectral dependence at UV wavelengths...
November 11, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27830788/tracking-the-ultrafast-motion-of-a-single-molecule-by-femtosecond-orbital-imaging
#20
Tyler L Cocker, Dominik Peller, Ping Yu, Jascha Repp, Rupert Huber
Watching a single molecule move on its intrinsic timescale has been one of the central goals of modern nanoscience, and calls for measurements that combine ultrafast temporal resolution with atomic spatial resolution. Steady-state experiments access the requisite spatial scales, as illustrated by direct imaging of individual molecular orbitals using scanning tunnelling microscopy or the acquisition of tip-enhanced Raman and luminescence spectra with sub-molecular resolution. But tracking the intrinsic dynamics of a single molecule directly in the time domain faces the challenge that interactions with the molecule must be confined to a femtosecond time window...
November 9, 2016: Nature
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