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https://www.readbyqxmd.com/read/28732306/photostability-testing-using-online-reactor-hplc-hyphenation-and-mass-spectrometric-compound-identification-illustrated-by-ketoprofen-as-model-compound
#1
Jaber Assaf, Diego Zulkiewicz Gomes, Bernhard Wuest, Maria Kristina Parr
Investigations on the photochemical stability of pharmaceutical substances are mandatory in drug development and licensing as photo-induced degradation of an active pharmaceutical ingredient (API) may not only lead to decreased API concentrations but also to toxic or reactive products. Thus, the US Food and Drug Administration (FDA) and the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) issued Guidance for Industry Q1B "Photostability Testing of New Drug Substances and Products" for testing of pure but also packed drugs...
July 8, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28731691/singlet-oxygen-photophysics-in-liquid-solvents-converging-on-a-unified-picture
#2
Mikkel Bregnhøj, Michael Westberg, Boris F Minaev, Peter R Ogilby
Singlet oxygen, O2(a(1)Δg), the lowest excited electronic state of molecular oxygen, is an omnipresent part of life on earth. It is readily formed through a variety of chemical and photochemical processes, and its unique reactions are important not just as a tool in chemical syntheses but also in processes that range from polymer degradation to signaling in biological cells. For these reasons, O2(a(1)Δg) has been the subject of intense activity in a broad distribution of scientific fields for the past ∼50 years...
July 21, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28731118/correction-photoinduced-electron-transfer-across-an-organic-molecular-wall-octa-acid-encapsulated-esipt-dyes-as-electron-donors
#3
Fabiano S Santos, Elamparuthi Ramasamy, V Ramamurthy, Fabiano S Rodembusch
Correction for 'Photoinduced electron transfer across an organic molecular wall: octa acid encapsulated ESIPT dyes as electron donors' by Fabiano S. Santos et al., Photochem. Photobiol. Sci., 2017, 16, 840-844.
July 21, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28730822/distributions-of-polycyclic-aromatic-hydrocarbons-aromatic-ketones-carboxylic-acids-and-trace-metals-in-arctic-aerosols-long-range-atmospheric-transport-and-photochemical-degradation-production-at-polar-sunrise
#4
Dharmendra Kumar Singh, Kimitaka Kawamura, Ayako Yanase, Leonard Barrie
The distributions, correlations and source apportionment of aromatic acids, aromatic ketones, polycyclic aromatic hydrocarbons (PAHs) and trace metals were studied in Canadian high Arctic aerosols. 19 PAHs including minor sulphur-containing heterocyclic PAH (dibenzothiophene) and major 6 carcinogenic PAHs were detected with a high proportion of fluoranthene followed by benzo[k]fluoranthene, pyrene and chrysene. However, in the sunlit period of spring, their concentrations significantly declined likely due to photochemical decomposition...
July 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28729902/high-tolerance-to-high-light-conditions-for-the-protected-species-ariocarpus-kotschoubeyanus-cactaceae
#5
Erika Arroyo-Pérez, Joel Flores, Claudia González-Salvatierra, María L Matías-Palafox, Cecilia Jiménez-Sierra
We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the 'living rock' cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (ΦPSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photosynthetically active photon flux density for PSII (PFDsat) were also determined from rapid light curves...
2017: Conservation Physiology
https://www.readbyqxmd.com/read/28729656/endolysosomal-targeting-of-a-clinical-chlorin-photosensitiser-for-light-triggered-delivery-of-nano-sized-medicines
#6
Elnaz Yaghini, Ruggero Dondi, Kunal M Tewari, Marilena Loizidou, Ian M Eggleston, Alexander J MacRobert
A major problem with many promising nano-sized biotherapeutics including macromolecules is that owing to their size they are subject to cellular uptake via endocytosis, and become entrapped and then degraded within endolysosomes, which can significantly impair their therapeutic efficacy. Photochemical internalisation (PCI) is a technique for inducing cytosolic release of the entrapped agents that harnesses sub-lethal photodynamic therapy (PDT) using a photosensitiser that localises in endolysosomal membranes...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28729303/amotosalen-uva-pathogen-inactivation-technology-reduces-platelet-activatability-induces-apoptosis-and-accelerates-clearance
#7
Simona Stivala, Sara Gobbato, Laura Infanti, Martin F Reiner, Nicole Bonetti, Sara C Meyer, Giovanni G Camici, Thomas F Lüscher, Andreas Buser, Jürg H Beer
Amotosalen and ultraviolet A photochemical-based pathogen reduction using the InterceptTM Blood System is an effective and established technology for platelet and plasma components, which is adopted in more than 40 countries worldwide. Several reports point towards a reduced platelet function after Amotosalen/UVA exposure. The current study was undertaken to identify the mechanisms responsible for the early impairment of platelet function by the InterceptTM Blood System. Twenty-five platelet apheresis units were collected from healthy volunteers following standard procedures and split into 2 components, one untreated and the other treated with Amotosalen/UVA...
July 20, 2017: Haematologica
https://www.readbyqxmd.com/read/28726903/reversible-trans-%C3%A2-cis-photoisomerizations-of-re-co-3-ph2phen-stpycn-towards-molecular-machines
#8
Kassio P S Zanoni, Neyde Y Murakami Iha
In our search for light powered molecular devices, a novel fac-[Re(CO)3(ph2phen)(trans-stpyCN)](+) complex was synthesized to show switchable trans-cis configurations of the coordinated stpyCN ligand through efficient and reversible photoassisted isomerizations. Controlled photolyses of acetonitrile solutions led to spectral changes ascribed to reversible trans ⇌ cis photoisomerization processes. A remarkable quantum yield for the back cis-to-trans isomerization was obtained, with the same magnitude of the trans-to-cis photoprocess, and curiously, both trans- and cis-isomers are emissive at room temperature...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726891/frontier-orbitals-of-photosubstitutionally-active-ruthenium-complexes-an-experimental-study-of-the-spectator-ligands-electronic-properties-influence-on-photoreactivity
#9
Hyo Jin Jang, Samantha L Hopkins, Maxime A Siegler, Sylvestre Bonnet
The synthesis and characterization of [Ru(tpy)(R2bpy)(L)](X)n complexes (tpy = 2,2':6',2''-terpyridine, R2bpy = 4,4'-dimethyl-2,2'-bipyridine (dmbpy), or 4,4'-bis(trifluoromethyl)-2,2'-bipyridine (tfmbpy), X = Cl(-) or PF6(-), and n = 1 or 2) are described. The dmbpy and tfmbpy bidentate ligands allow for investigating the effects of electron-donating and electron-withdrawing ligands, respectively, on the frontier orbital energetics as well as the photoreactivity of these ruthenium polypyridyl complexes for five prototypical monodentate ligands L = Cl(-), H2O, CH3CN, 2-(methylthio)ethanol (Hmte), or pyridine...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726387/aryl-substituted-ruthenium-ii-complexes-a-strategy-for-enhanced-photocleavage-and-efficient-dna-binding
#10
Felipe Diógenes Abreu, Tercio de F Paulo, Marcelo H Gehlen, Rômulo A Ando, Luiz G F Lopes, Ana Cláudia S Gondim, Mayron A Vasconcelos, Edson H Teixeira, Eduardo Henrique Silva Sousa, Idalina Maria Moreira de Carvalho
Ruthenium polypyridine complexes have shown promise as agents for photodynamic therapy (PDT) and tools for molecular biology (chromophore-assisted light inactivation). To accomplish these tasks, it is important to have at least target selectivity and great reactive oxygen species (ROS) photogeneration: two properties that are not easily found in the same molecule. To prepare such new agents, we synthesized two new ruthenium complexes that combine an efficient DNA binding moiety (dppz ligand) together with naphthyl-modified (1) and anthracenyl-modified (2) bipyridine as a strong ROS generator bound to a ruthenium complex...
July 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28726385/low-temperature-post-functionalization-of-highly-conductive-oxide-thin-films-toward-solution-based-large-scale-electronics
#11
Seok-Gyu Ban, Kyung-Tae Kim, Byung Doo Choi, Jeong-Wan Jo, Yong-Hoon Kim, Antonio Facchetti, Myung-Gil Kim, Sung Kyu Park
Although transparent conducting oxides (TCOs) have played a key role in a wide range of solid-state electronics from conventional optoelectronics to emerging electronic systems, the processing temperature and conductivity of solution-processed materials seem to be far exceeding the thermal limitations of soft materials and insufficient for high-perfomance large-area systems, respectively. Here, we report a strategy to form highly conductive and scalable solution-processed oxide materials and their successful translation into large-area electronic applications, which is enabled by photo-assisted post-functionalization at low-temperature...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28726222/loss-of-crop-yields-in-india-due-to-surface-ozone-an-estimation-based-on-a-network-of-observations
#12
Shyam Lal, Sethuraman Venkataramani, Manish Naja, Jagdish Chandra Kuniyal, Tuhin Kumar Mandal, Pradip Kumar Bhuyan, Kandikonda Maharaj Kumari, Sachchida Nand Tripathi, Ujjaini Sarkar, Trupti Das, Yerramsetti Venkata Swamy, Kotalo Rama Gopal, Harish Gadhavi, Modathi Kottungal Satheesh Kumar
Surface ozone is mainly produced by photochemical reactions involving various anthropogenic pollutants, whose emissions are increasing rapidly in India due to fast-growing anthropogenic activities. This study estimates the losses of wheat and rice crop yields using surface ozone observations from a group of 17 sites, for the first time, covering different parts of India. We used the mean ozone for 7 h during the day (M7) and accumulated ozone over a threshold of 40 ppbv (AOT40) metrics for the calculation of crop losses for the northern, eastern, western and southern regions of India...
July 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28725228/unraveling-the-photoprotective-response-of-lichenized-and-free-living-green-algae-trebouxiophyceae-chlorophyta-to-photochilling-stress
#13
Fátima Míguez, Ulf Schiefelbein, Ulf Karsten, José I García-Plazaola, Lydia Gustavs
Lichens and free-living terrestrial algae are widespread across many habitats and develop successfully in ecosystems where a cold winter limits survival. With the goal of comparing photoprotective responses in free-living and lichenized algae, the physiological responses to chilling and photochilling conditions were studied in three lichens and their isolated algal photobionts together as well as in a fourth free-living algal species. We specifically addressed the following questions: (i) Are there general patterns of acclimation in green algae under chilling and photochilling stresses? (ii) Do free-living algae exhibit a similar pattern of responses as their lichenized counterparts? (iii) Are these responses influenced by the selection pressure of environmental conditions or by the phylogenetic position of each species? To answer these questions, photosynthetic fluorescence measurements as well as pigment and low molecular weight carbohydrate pool analyses were performed under controlled laboratory conditions...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28724227/carbon-and-nitrogen-allocation-strategy-in-posidonia-oceanica-is-altered-by-seawater-acidification
#14
Andrea Scartazza, Stefano Moscatello, Olga Gavrichkova, Maria Cristina Buia, Marco Lauteri, Alberto Battistelli, Maurizio Lorenti, Samantha Laird Garrard, Carlo Calfapietra, Enrico Brugnoli
Rising atmospheric CO2 causes ocean acidification that represents one of the major ecological threats for marine biota. We tested the hypothesis that long-term exposure to increased CO2 level and acidification in a natural CO2 vent system alters carbon (C) and nitrogen (N) metabolism in Posidonia oceanica L. (Delile), affecting its resilience, or capability to restore the physiological homeostasis, and the nutritional quality of organic matter available for grazers. Seawater acidification decreased the C to N ratio in P...
July 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28723895/visible-light-driven-methane-formation-from-co2-with-a-molecular-iron-catalyst
#15
Heng Rao, Luciana C Schmidt, Julien Bonin, Marc Robert
Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare...
July 17, 2017: Nature
https://www.readbyqxmd.com/read/28723091/protomer-specific-photochemistry-investigated-using-ion-mobility-mass-spectrometry
#16
James N Bull, Neville J A Coughlan, Evan John Bieske
The utility of tandem ion mobility mass spectrometry coupled with electronic spectroscopy to investigate protomer-specific photochemistry is demonstrated by measuring the photoisomerization response for protomers of protonated 4-dicyanomethylene-2-methyl-6-para-dimethylaminostyryl-4H-pyran (DCM) molecules. The target DCMH(+) species, has three protomers that are distinguished by their different collision cross-sections with He, N2, and CO2 buffer gases, trends in abundance with ion source conditions, and from their photoisomerization responses...
July 19, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28723081/fluorescent-molecular-probes-for-detection-of-one-electron-oxidants-photochemically-generated-by-dissolved-organic-matter
#17
Vivian S Lin, Matthew Grandbois, Kristopher McNeill
We report a dual probe system based on 4'-substituted biphenyl-2-carboxylic acids (BPAs) for analysis of photooxidants generated by dissolved organic matter. The BPA probes are converted to the corresponding benzocoumarins (BZCs) at different rates depending on the mechanism of oxidation; thus, two probes used simultaneously can differentiate strong triplet excited state sensitizers from hydroxylating species such as hydroxyl radical (•OH) present in dissolved organic matter (DOM). Comparison of the ratios of BZC-CH3 and BZC-CF3 product formation using model photooxidants such as NaNO2, a •OH precursor, and model triplet sensitizer lumichrome gave a range of 2 to 250...
July 19, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28723072/superposition-principle-in-auger-recombination-of-charged-and-neutral-multicarrier-states-in-semiconductor-quantum-dots
#18
Kaifeng Wu, Jaehoon Lim, Victor I Klimov
Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation of extra charges, which opens fast nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the extra-carrier(s) and ultimately dissipated as heat. Previous studies of Auger recombination have primarily focused on neutral, and more recently, negatively charged multi-carrier states. Auger dynamics of positively charged species remains more poorly explored due to difficulties in creating, stabilizing, and detecting excess holes in the QDs...
July 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/28722272/development-of-a-thiol-ene-based-screening-platform-for-enzyme-immobilization-demonstrated-using-horseradish-peroxidase
#19
Christian Hoffmann, Manuel Pinelo, John M Woodley, Anders E Daugaard
Efficient immobilization of enzymes on support surfaces requires an exact match between the surface chemistry and the specific enzyme. A successful match would normally be identified through time consuming screening of conventional resins in multiple experiments testing individual immobilization strategies. In this study we present a versatile strategy that largely expands the number of possible surface functionalities for enzyme immobilization in a single, generic platform. The combination of many individual surface chemistries and thus immobilization methods in one modular system permits faster and more efficient screening, which we believe will result in a higher chance of discovery of optimal surface/enzyme interactions...
July 19, 2017: Biotechnology Progress
https://www.readbyqxmd.com/read/28721563/terrestrial-adaptation-of-green-algae-klebsormidium-and-zygnema-charophyta-involves-diversity-in-photosynthetic-traits-but-not-in-co2-acquisition
#20
Mattia Pierangelini, David Ryšánek, Ingeborg Lang, Wolfram Adlassnig, Andreas Holzinger
The basal streptophyte Klebsormidium and the advanced Zygnema show adaptation to terrestrialization. Differences are found in photoprotection and resistance to short-term light changes, but not in CO 2 acquisition. Streptophyte green algae colonized land about 450-500 million years ago giving origin to terrestrial plants. We aim to understand how their physiological adaptations are linked to the ecological conditions (light, water and CO2) characterizing modern terrestrial habitats. A new Klebsormidium isolate from a strongly acidic environment of a former copper mine (Schwarzwand, Austria) is investigated, in comparison to Klebsormidium cf...
July 18, 2017: Planta
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