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https://www.readbyqxmd.com/read/28091849/dynamic-optical-absorption-characteristics-of-blood-after-slow-and-fast-heating
#1
Hao Jia, Bin Chen, Dong Li
Laser treatment is the most effective therapy in dermatology for vascular skin disorders, such as port-wine stains (PWS). Changes in heat-induced absorbance in blood must be determined for accurate numerical simulation and implementation of multi-pulse laser therapy for treatment of PWS. Thermally induced absorbance changes in hemoglobin in blood were compared in vitro between slow water bath heating and fast heating irradiated by using sub-millisecond Nd:YAG laser. Blood composition at different temperatures was calculated by comparing blood absorption spectra with those of pure HbO2, Hb, and metHb at room temperature...
January 13, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28091673/conformational-and-electronic-effects-on-the-formation-of-anti-cyclobutane-pyrimidine-dimers-in-g-quadruplex-structures
#2
Wook Lee, Spiridoula Matsika
Cyclobutane pyrimidine dimers (CPDs) are the most commonly formed photochemical products when nucleic acids interact with UV radiation. In duplex DNA, the relative inflexible structure allows for only the cis, syn CPD isomer to be formed. G-quadruplex structures, however, have loops that are more flexible and allow for different orientations of the bases to interact. As a result, the highly unusual formation of an anti CPD has been observed in these structures. Due to the close proximity between two opposing loops containing the TTA sequence in two G-quadruplex structures (called "form-3" and "basket"), a high yield of anti CPD formation was expected in these structures...
January 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28088880/recent-advances-in-light-responsive-on-demand-drug-delivery-systems
#3
Chase S Linsley, Benjamin M Wu
The convergence of wearable sensors and personalized medicine enhance the ability to sense and control the drug composition and dosage, as well as location and timing of administration. To date, numerous stimuli-triggered smart drug-delivery systems have been developed to detect changes in light, pH, temperature, biomolecules, electric field, magnetic field, ultrasound and mechanical forces. This review examines the major advances within the last 5 years for the three most common light-responsive drug delivery-on-demand strategies: photochemical, photoisomerization and photothermal...
February 2017: Therapeutic Delivery
https://www.readbyqxmd.com/read/28088299/retraction-notice-to-influence-of-humic-acid-on-the-stability-and-bacterial-toxicity-of-zinc-oxide-nanoparticles-in-water-j-photochem-photobiol-b-biol-153-2015-289-295
#4
K Akhil, Preethy Chandran, S Sudheer Khan
No abstract text is available yet for this article.
January 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28088298/retraction-notice-to-synthesis-and-characterization-of-silver-sulfide-nanoparticles-for-photocatalytic-and-antimicrobial-applications-j-photochem-photobiol-b-biol-141-2014-235-240
#5
Pooja Kumari, Preethy Chandran, S Sudheer Khan
No abstract text is available yet for this article.
January 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28088164/photochemical-generation-of-h2ncnx-h2nncx-h2nc-nx-x-o-s-in-low-temperature-matrices
#6
Tamás Vörös, Győző György Lajgút, Gábor Magyarfalvi, György Tarczay
The [NH2, C, N, O] and the [NH2, C, N, S] molecular systems were investigated by computational and matrix-isolation spectroscopic methods. The determination of the equilibrium structures and relative energies by CCSD(T) method was followed by the computation of the harmonic and anharmonic vibrational wavenumbers, infrared intensities, relative Raman activities, and UV excitation energies. These computed data were used to assist the identification of products obtained by UV laser photolysis of 3,4-diaminofurazan and 3,4-diaminothiadiazole in low-temperature Ar and Kr matrices...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088146/photoinduced-c-i-bond-homolysis-of-5-iodouracil-a-singlet-predissociation-pathway
#7
Xiaojuan Dai, Di Song, Kunhui Liu, Hongmei Su
5-Iodouracil (5-IU) can be integrated into DNA and acts as a UV sensitive chromophore suitable for probing DNA structure and DNA-protein interactions based on the photochemical reactions of 5-IU. Here, we perform joint studies of time-resolved Fourier transform infrared (TR-FTIR) spectroscopy and ab initio calculations to examine the state-specific photochemical reaction mechanisms of the 5-IU. The fact that uracil (U) is observed in TR-FTIR spectra after 266 nm irradiation of 5-IU in acetonitrile and ascribed to the product of hydrogen abstraction by the uracil-5-yl radical (U·) provides experimental evidence for the C-I bond homolysis of 5-IU...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28088106/uv-a-induced-delayed-development-in-the-larvae-of-coral-seriatopora-caliendrum
#8
Jie Zhou, Tung-Yung Fan, John Beardall, Kunshan Gao
Coral reefs are vulnerable to ultraviolet radiation (UVR, 280-400nm). Not only do the fluxes of UVR fluctuate daily, they are also increasing due to global ocean and atmospheric changes. The deleterious effects of UVR on scleractinian corals have been intensively studied, but much less is known about the response of corals in the early pre-settlement phase. In this study, we tested how UVR exposure affects survival and development of Seriatopora caliendrum larvae and examined the photophysiological changes induced in the symbiotic dinoflagellate Symbiodinium...
January 4, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28080052/mechanochemical-tuning-of-pyrene-absorption-spectrum-using-force-probes
#9
Miguel Angel Fernández-González, Daniel Rivero, Cristina García-Iriepa, Diego Sampedro, Luis Manuel Frutos
Control of absorption spectra in chromophores is a fundamental aspect of many photochemical and photophysical processes as it constitutes the first step of the global photoinduced process. Here we explore the use of mechanical forces to modulate the light absorption process. Specifically, we develop a computational formalism for determining the type of mechanical forces permitting a global tuning of the absorption spectrum. This control extends to the excitation wavelength, absorption bands overlap and oscillator strength...
January 12, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28078764/photoisomerization-of-a-chiral-imine-molecular-switch-followed-by-matrix-isolation-vcd-spectroscopy
#10
Corina H Pollok, Tim Riesebeck, Christian Merten
Characterizing the stereochemistry of transient photoisomerization products remains a big challenge for the design of molecular machines, such as unidirectional molecular motors. Often these states are not stable long enough to be characterized in detail using conventional spectroscopic tools. The structurally simple camphorquinone imine 1 serves to illustrate the advantage of combining the matrix-isolation technique with vibrational circular dichroism (VCD) spectroscopy for the investigation of photoisomerizations of chiral molecules...
January 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28076815/fluorescent-labeling-preserving-ocp-photoactivity-reveals-its-reorganization-during-the-photocycle
#11
Eugene G Maksimov, Nikolai N Sluchanko, Kirill S Mironov, Evgeny A Shirshin, Konstantin E Klementiev, Georgy V Tsoraev, Marcus Moldenhauer, Thomas Friedrich, Dmitry A Los, Suleyman I Allakhverdiev, Vladimir Z Paschenko, Andrei B Rubin
Orange carotenoid protein (OCP), responsible for the photoprotection of the cyanobacterial photosynthetic apparatus under excessive light conditions, undergoes significant rearrangements upon photoconversion and transits from the stable orange to the signaling red state. This is thought to involve a 12-Å translocation of the carotenoid cofactor and separation of the N- and C-terminal protein domains. Despite clear recent progress, the detailed mechanism of the OCP photoconversion and associated photoprotection remains elusive...
January 10, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28075578/probing-structural-perturbation-in-a-bent-molecular-crystal-with-synchrotron-infrared-microspectroscopy-and-periodic-density-functional-theory-calculations
#12
Ljupco Pejov, Manas K Panda, Taro Moriwaki, Pance Naumov
The range of unit cell orientations generated at the kink of a bent single crystal poses unsurmountable challenges with diffraction analysis and limits the insight into the molecular-scale mechanism of bending. On a plastically bent crystal of hexachlorobenzene it is demonstrated here that spatially resolved microfocus infrared spectroscopy using synchrotron radiation can be applied in conjunction with periodic density functional theory calculations to predict spectral changes or to extract information on structural changes that occur as a consequence of bending...
January 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28075129/substituted-diarylnorbornadienes-and-quadricyclanes-synthesis-photochemical-properties-and-effect-of-substituent-on-the-kinetic-stability-of-quadricyclanes
#13
Kyle J Spivack, Jesse V Walker, Maria J Sanford, Benjamin R Rupert, Andrew R Ehle, James M Tocyloski, Aaron N Jahn, Lyndsey M Shaak, Obiamaka Obianyo, Karyn M Usher, Felix Emmett Goodson
In this paper we present a new method for the synthesis of diarylnorbornadiene derivatives. Through the use of a two-step procedure consisting of a tandem alkene insertion-Suzuki coupling reaction followed by a DDQ dehydrogenation, we have been able to synthesize derivatives with a wide variety of substituents. We also present the results of UV-Visible spectroscopy studies and kinetics experiments that show the effect of substituent on light absorption properties of the norbornadienes as well as the kinetic stability of the quadricyclanes that result from their photochemical conversion...
January 11, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28075059/photochemically-driven-polymeric-network-formation-synthesis-and-applications
#14
Eva Blasco, Martin Wegener, Christopher Barner-Kowollik
Polymeric networks have been intensely investigated and a large number of applications have been found in areas ranging from biomedicine to materials science. Network fabrication via light-induced reactions is a particularly powerful tool, since light provides ready access to temporal and spatial control, opening an array of synthetic access routes for structuring the network geometry as well as functionality. Herein, the most recent light-induced modular reactions and their use in the formation of precision polymeric networks are collated...
January 11, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28072547/mild-photochemical-biofunctionalization-of-glass-microchannels
#15
Rui Rijo Carvalho, Sidharam P Pujari, Digvijay Gahtory, Elwin X Vrouwe, Bauke Albada, Han Zuilhof
The ability to locally modify the inside of microfluidic channels with bioactive molecules is of ever-rising relevance. In this article, we show the direct photochemical coupling of a N-hydroxysuccinimide-terminated ω-alkene onto hydrogen-terminated silicon oxide, and its subsequent functionalization with a catalytically active DNAzyme. To achieve this local attachment of a DNAzyme, we prepared hydrogen-phenyl-terminated glass (H-Φ-glass) by the reaction of glass with H-SiPhCl2. The presence of a radical-stabilizing substituent on the Si atom (i...
January 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28071849/activation-of-the-b-f-bond-by-diphenylcarbene-a-reversible-1-2-fluorine-migration-between-boron-and-carbon
#16
Paolo Costa, Joel Mieres Perez, Nesli Özkan, Wolfram Sander
Experiments in low-temperature matrices reveal that triplet diphenylcarbene inserts into the very strong B-F bond of BF3 in a two-step reaction. The first step is the formation of a strongly bound Lewis acid-base complex between the singlet state of diphenylcarbene and BF3 . This step involves an inversion of the spin state of the carbene from triplet to singlet. The second step requires visible-light photochemical activation to induce a 1,2-F migration from boron to the adjacent carbon atom under formation of the formal insertion product of the carbene center into BF3 ...
January 10, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28071047/linking-load-fuel-and-emission-controls-to-photochemical-production-of-secondary-organic-aerosol-from-a-diesel-engine
#17
Shantanu H Jathar, Beth Friedman, Abril A Galang, Michael F Link, Patrick Brophy, John Volckens, Sailaja Eluri, Delphine K Farmer
Diesel engines are important sources of fine particle pollution in urban environments but their contribution to the atmospheric formation of secondary organic aerosol (SOA) is not well constrained. We investigated direct emissions of primary organic aerosol (POA) and photochemical production of SOA from a diesel engine using an oxidation flow reactor (OFR). In less than a day of simulated atmospheric aging, SOA production exceeded POA emissions by an order of magnitude or more. Efficient combustion at higher engine loads coupled to the removal of SOA precursors and particle emissions by aftertreatment systems reduced POA emission factors by an order of magnitude and SOA production factors by factors of 2-10...
January 10, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28069780/a-chlorophyll-fluorescence-based-method-for-the-integrated-characterization-of-the-photophysiological-response-to-light-stress
#18
João Serôdio, William Schmidt, Silja Frankenbach
This work introduces a new experimental method for the comprehensive description of the physiological responses to light of photosynthetic organisms. It allows the integration in a single experiment of the main established manipulative chlorophyll fluorescence-based protocols. It enables the integrated characterization of the photophysiology of samples regarding photoacclimation state (generating non-sequential light-response curves of effective PSII quantum yield, electron transport rate or non-photochemical quenching), photoprotection capacity (running light stress-recovery experiments, quantifying non-photochemical quenching components) and the operation of photoinactivation and photorepair processes (measuring rate constants of photoinactivation and repair for different light levels and the relative quantum yield of photoinactivation)...
January 9, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28069306/nitrated-polycyclic-aromatic-hydrocarbons-nitro-pahs-in-the-environment-a-review
#19
REVIEW
Benjamin A Musa Bandowe, Hannah Meusel
Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are derivatives of PAHs with at least one nitro-functional group (-NO2) on the aromatic ring. The toxic effects of several nitro-PAHs are more pronounced than those of PAHs. Some nitro-PAHs are classified as possible or probable human carcinogens by the International Agency for Research on Cancer. Nitro-PAHs are released into the environment from combustion of carbonaceous materials (e.g. fossil fuels, biomass, waste) and post-emission transformation of PAHs...
January 6, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28068894/strain-differences-in-a-murine-model-of-air-pollutant-induced-nonatopic-asthma-and-rhinitis
#20
Jack R Harkema, Lucas A Hotchkiss, Nicholas A Vetter, Daven N Jackson-Humbles, Ryan P Lewandowski, James G Wagner
Ozone is an irritating gas found in photochemical smog. Epidemiological associations have been made between the onset of asthma and childhood exposures to increasing levels of ambient ozone (i.e., air pollutant-induced nonatopic asthma). Individuals, however, vary in their susceptibility to this outdoor air pollutant, which may be due, in part, to their genetic makeup. The present study was designed to test the hypothesis that there are murine strain-dependent differences in pulmonary and nasal pathologic responses to repeated ozone exposures...
January 2017: Toxicologic Pathology
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