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https://www.readbyqxmd.com/read/28636018/fluorescence-lifetime-microscopy-reveals-the-biologically-related-photophysical-heterogeneity-of-oxyblepharismin-in-light-adapted-blue-blepharisma-japonicum-cells
#1
G Checcucci, B Storti, F Ghetti, G Signore, R Bizzarri
The step-up photophobic response of the heterotrich ciliate Blepharisma japonicum is mediated by a hypericinic pigment, blepharismin, which is not present in any of the known six families of photoreceptors, namely rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. Upon irradiation, native cells become light-adapted (blue) by converting blepharismin into the photochemically stable oxyblepharismin (OxyBP). So far, OxyBP has been investigated mainly from a photophysical point of view in vitro, either alone or complexed with proteins...
June 21, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28633853/multi-objective-optimization-of-oxidative-desulfurization-in-a-sono-photochemical-airlift-reactor
#2
Jamshid Behin, Negin Farhadian
Response surface methodology (RSM) was employed to optimize ultrasound/ultraviolet-assisted oxidative desulfurization in an airlift reactor. Ultrasonic waves were incorporated in a novel-geometry reactor to investigate the synergistic effects of sono-chemistry and enhanced gas-liquid mass transfer. Non-hydrotreated kerosene containing sulfur and aromatic compounds was chosen as a case study. Experimental runs were conducted based on a face-centered central composite design and analyzed using RSM. The effects of two categorical factors, i...
September 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28633106/selective-photocytotoxicity-of-anthrols-on-cancer-stem-like-cells-the-effect-of-quinone-methides-or-reactive-oxygen-species
#3
Lidija Uzelac, Đani Škalamera, Kata Mlinarić-Majerski, Nikola Basarić, Marijeta Kralj
Cancer stem cells (CSCs) are a subpopulation of cancer cells that share properties of embryonic stem cells like pluripotency and self-renewal and show increased resistance to chemo- and radiotherapy. Targeting CSC, rather than cancer cells in general, is a novel and promising strategy for cancer treatment. Novel therapeutic approaches, such as photodynamic therapy (PDT) have been investigated. A promising group of phototherapeutic agents are reactive intermediates - quinone methides (QMs). This study describes preparation of QM precursor, 2-hydroxy-3-hydroxymethylanthracene (2) and a detailed photochemical and photobiological investigation on similar anthracene derivatives 3 and 4...
June 3, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28632317/qm-mm-study-on-the-photoreactions-of-dark-and-light-adapted-states-of-a-blue-light-ytva-lov-photoreceptor
#4
Xue-Ping Chang, Yuan-Jun Gao, Wei-Hai Fang, Ganglong Cui, Walter Thiel
The dark- and light-adapted states of YtvA LOV domains exhibit distinct excited-state behavior. We have employed high-level QM(MS-CASPT2)/MM calculations to study the photochemical reactions of the dark- and light-adapted states. The photoreaction from the dark-adapted state starts with an S1→T1 intersystem crossing followed by a triplet-state hydrogen transfer from the thiol to the flavin moiety that produces a diradical intermediate, and a subsequent internal conversion that triggers a barrierless C-S bond formation in the S0 state...
June 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28629848/a-novel-intrinsic-electroretinogram-response-in-isolated-mouse-retina
#5
Motoharu Takao, Yumi Fukuda, Takeshi Morita
Since the discovery of intrinsic photosensitive retinal ganglion cell (ipRGC) was reported in 2002, many features specific to this cell type have been described. However, scare information is available on the retinographic components directly reflecting ipRGC activity. In this study, we identified the electroretinogram (microERG) that reflects the photoresponses by ipRGCs in ex vivo preparations of the mouse retina, in which classical photoreceptors (cones and rods) were ablated mechanically and photochemically...
June 16, 2017: Neuroscience
https://www.readbyqxmd.com/read/28628881/photodegradation-and-ecotoxicology-of-acyclovir-in-water-under-uv254-and-uv254-h2o2-processes
#6
Danilo Russo, Antonietta Siciliano, Marco Guida, Emilia Galdiero, Angela Amoresano, Roberto Andreozzi, Nuno M Reis, Gianluca Li Puma, Raffaele Marotta
The photochemical and ecotoxicological fate of acyclovir (ACY) through UV254 direct photolysis and in the presence of hydroxyl radicals (UV254/H2O2 process) were investigated in a microcapillary film (MCF) array photoreactor, which provided ultrarapid and accurate photochemical reaction kinetics. The UVC phototransformation of ACY was found to be unaffected by pH in the range from 4.5 to 8.0 and resembled an apparent autocatalytic reaction. The proposed mechanism included the formation of a photochemical intermediate (ϕACY = (1...
June 7, 2017: Water Research
https://www.readbyqxmd.com/read/28628819/dissolved-gaseous-mercury-formation-and-mercury-volatilization-in-intertidal-sediments
#7
Rute Cesário, Laurier Poissant, Martin Pilote, Nelson J O'Driscoll, Ana M Mota, João Canário
Intertidal sediments of Tagus estuary regularly experiences complex redistribution due to tidal forcing, which affects the cycling of mercury (Hg) between sediments and the water column. This study quantifies total mercury (Hg) and methylmercury (MMHg) concentrations and fluxes in a flooded mudflat as well as the effects on water-level fluctuations on the air-surface exchange of mercury. A fast increase in dissolved Hg and MMHg concentrations was observed in overlying water in the first 10min of inundation and corresponded to a decrease in pore waters, suggesting a rapid export of Hg and MMHg from sediments to the water column...
June 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28628318/third-generation-light-driven-symmetric-molecular-motors
#8
Jos C M Kistemaker, Peter Stacko, Diederik Roke, Alexander Thomas Wolters, G Henrieke Heideman, Mu-Chieh Chang, Pieter van der Meulen, Johan Visser, Edwin Otten, Ben L Feringa
Symmetric molecular motors based on two overcrowded alkenes with a notable absence of a stereogenic center show potential to function as novel mechanical systems in the development of more advanced nanomachines and controlled motion over surfaces. Elucidation of the key parameters and limitations of these third generation motors is essential for the design of optimized molecular machines based on light-driven rotary motion. Herein we demonstrate the thermal and photochemical rotational behavior of a series of third generation light-driven molecular motors...
June 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28628230/thread-like-cmos-logic-circuits-enabled-by-reel-processed-single-walled-carbon-nanotube-transistors-via-selective-doping
#9
Jae Sang Heo, Taehoon Kim, Seok-Gyu Ban, Daesik Kim, Jun Ho Lee, Jesse S Jur, Myung-Gil Kim, Yong-Hoon Kim, Yongtaek Hong, Sung Kyu Park
The realization of large-area electronics with full integration of 1D thread-like devices may open up a new era for ultraflexible and human adaptable electronic systems because of their potential advantages in demonstrating scalable complex circuitry by a simply integrated weaving technology. More importantly, the thread-like fiber electronic devices can be achieved using a simple reel-to-reel process, which is strongly required for low-cost and scalable manufacturing technology. Here, high-performance reel-processed complementary metal-oxide-semiconductor (CMOS) integrated circuits are reported on 1D fiber substrates by using selectively chemical-doped single-walled carbon nanotube (SWCNT) transistors...
June 19, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28625052/photochemical-kinetics-of-a-phosphine-oxide-free-radical-initiator-from-femtosecond-uv-pump-mid-ir-probe-spectroscopy
#10
Steffen Straub, Joerg Lindner, Peter Vohringer
Femtosecond UV-pump/mid-infrared-probe spectroscopy was used to explore in detail the primary photochemical events of the free radical initiator, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, in liquid dichloromethane solution at room temperature. Following electronic excitation of its lowest excited singlet state, S1, the radical initiator undergoes an intersystem crossing to the triplet ground state, T1, with a time constant of 135 ps. A subsequent α-cleavage occurs from the triplet state with a time constant of 15 ps and yields a trimethylbenzoyl radical together with a diphenylphosphinoyl radical...
June 18, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28625051/excited-state-deactivation-pathways-and-the-photocyclization-of-bn-doped-polyaromatics
#11
Joshua A Snyder, Peter Grüninger, Holger F Bettinger, Arthur E Bragg
Boron-nitrogen doping of polyaromatic hydrocarbons (PAH), such as borazine-core hexabenzocoronene, presents possibilities for tuning the properties of organic electronics and nanographene materials while preserving structural characteristics of pure hydrocarbons. Previous photochemical studies have demonstrated extension of a borazine-core PAH network (1,2:3,4:5,6 tris(o,o'-biphenylylene) borazine, 1) by photoinduced cyclodehydrogenation. We present steady-state and fs-to-μs resolved spectroscopic studies of the photophysics of 1 and a related borazine-core PAH in order to characterize competing excited-state relaxation pathways that determine the efficacy of bond formation by photocyclization...
June 18, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28624737/optical-properties-of-the-human-lens-constituents
#12
Ekaterina A Zelentsova, Lyudmila V Yanshole, Anjella Zh Fursova, Yuri P Tsentalovich
The absorption and fluorescence properties of the metabolomic (MET), water-soluble and urea-soluble protein fractions from the middle-age, aged, and cataractous human lenses have been measured. At 280nm and 300nm the major lens absorbers are crystallins, which absorb more than 90% of light in the UV-B region (280-315nm). In middle-aged lenses, the absorption at 360nm is mostly provided by UV filters contained in the MET fraction. With aging, and especially with the cataract development, the absorption of MET fraction in UV-A region (315-400nm) decreases due to the drop of the UV filter concentration, while the absorption of protein fractions increases due to the accumulation of post-translational modifications...
June 3, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28624684/photoprotection-regulated-by-phosphorus-application-can-improve-photosynthetic-performance-and-alleviate-oxidative-damage-in-dwarf-bamboo-subjected-to-water-stress
#13
Chenggang Liu, Yanjie Wang, Yanqiang Jin, Kaiwen Pan, Xingmei Zhou, Na Li
Water and nutrients, particularly phosphorus (P), are the two most limiting factors for dwarf bamboo growth in tropical and subtropical areas. Dwarf bamboo is highly sensitive to water stress and often causes severe P deficiency in its growing soils due to the characteristics of shallower roots and expeditious growth. However, little is known about its photoprotective response to soil water deficit and the underlying mechanisms regulated by P application. In this study, a completely randomized design with two factors of two water regimes (well-watered and water-stressed) and two P levels (with and without P application) was arranged to investigate this issue in dwarf bamboo (Fargesia rufa) plants...
June 8, 2017: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/28624639/ozone-exposure-and-flux-based-response-relationships-with-photosynthesis-leaf-morphology-and-biomass-in-two-poplar-clones
#14
Bo Shang, Zhaozhong Feng, Pin Li, Xiangyang Yuan, Yansen Xu, Vicent Calatayud
Poplar clones 546 (P. deltoides cv. '55/56'×P. deltoides cv. 'Imperial') and 107 (P. euramericana cv. '74/76') were exposed to five ozone concentrations in 15 open-top chambers (OTCs). Both ozone exposure (AOT40, Accumulation Over a Threshold hourly ozone concentration of 40ppb) and flux-based (POD7, Phytotoxic Ozone Dose above an hourly flux threshold of 7nmol O3 m(-2) PLA (projected leaf area) s(-1)) response relationships were established with photosynthesis, leaf morphology and biomass variables. Increases in both metrics showed significant negative relationships with light-saturated photosynthesis rate, chlorophyll content, leaf mass per area, actual photochemical efficiency of PSII in the light and root biomass but not with stomatal conductance (gs), leaf and stem biomass...
June 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28622542/on-the-mechanism-of-non-radiative-decay-of-blue-fluorescent-protein-chromophore-new-insight-from-the-excited-state-molecular-dynamics-simulations-and-potential-energy-calculations
#15
Li Zhao, Jian-Yong Liu, Pan-Wang Zhou
A detailed theoretical investigation based on the ab initio on-the-fly surface hopping dynamics simulations and potential energy surfaces calculations has been performed to unveil the mechanism of the photoinduced non-adiabatic relaxation process of the isolated blue fluorescent protein (BFP) chromophore in gas phase. The data analysis presents that the dominant reaction coordinate of the BFP chromophore is driven by a rotation motion around the CC double bridging bond, which is in remarkable difference with a previous result which supports a Hula-Twist rotation pattern...
June 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28621947/cucurbit-7-uril-enables-multistimuli-responsive-release-from-the-self-assembled-hydrophobic-phase-of-a-metal-organic-polyhedron
#16
Soumen Samanta, Jeffrey Quigley, Brittany Vinciguerra, Volker Briken, Lyle Isaacs
Mixed self-assembly of ligand 1, 2, 1,6-hexanediamine (HDA) and Pd(NO3)2 afforded Fujita-type metal organic polyhedron MOP1 (diameter ≈ 8.2 nm) which is covalently functionalized with 18 cucurbit[7]uril (CB[7]) units as evidenced by 1H NMR, diffusion ordered spectroscopy NMR and transmission electron microscopy measurements. By virtue of the host-guest properties of CB[7], the inner cavity of MOP can be rendered hydrophobic by using alkylated HDA (3) as guest during self-assembly process. The hydrophobic cavity was successfully utilized to trap the hydrophobic dye Nile Red (NR) and the anticancer drug Doxorubicin (DOX)...
June 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28621913/visible-light-promoted-generation-of-alpha-ketoradicals-from-vinyl-bromides-and-molecular-oxygen-synthesis-of-indenones-and-dihydroindeno-1-2-c-chromenes
#17
Santosh K Pagire, Peter Kreitmeuer, Oliver Reiser
Ortho-alkynylated α-bromocinnamates can be converted by a visible light mediated photocascade reaction with molecular oxygen either to indenones or to dihydroindeno[1,2-c]chromenes. The one-step process features two photochemical key steps, i.e. the activation of vinyl bromides by energy transfer giving rise to α-ketoradicals in the reaction with molecular oxygen and the α-hydroxylation of an arene moiety.
June 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28621526/orthogonal-mass-spectrometry-based-footprinting-for-epitope-mapping-and-structural-characterization-the-il-6-receptor-upon-binding-of-protein-therapeutics
#18
Ke Sherry Li, Guodong Chen, Jingjie Mo, Richard Y-C Huang, Ekaterina G Deyanova, Brett R Beno, Steve O'Neil, Adrienne A Tymiak, Michael L Gross
Higher order structure (HOS) is a crucial determinant for the biological functions and quality attributes of protein therapeutics. Mass spectrometry (MS)-based protein footprinting approaches play an important role in elucidating the relationship between protein biophysical properties and structure. Here, we describe the use of a combined method including hydrogen-deuterium exchange (HDX), fast photochemical oxidation of proteins (FPOP) and site-specific carboxyl group footprinting to investigate the HOS of protein and protein complexes...
June 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28619535/evolution-and-regulation-of-bigelowiella-natans-light-harvesting-antenna-system
#19
Jonathan A D Neilson, Pattarasiri Rangsrikitphoti, Dion G Durnford
Bigelowiella natans is a mixotrophic flagellate and member of the chlorarachniophytes (Rhizaria), whose plastid is derived from a green algal endosymbiont. With the completion of the B. natans nuclear genome we are able to begin the analysis of the structure, function and evolution of the photosynthetic apparatus. B. natans has undergone substantial changes in photosystem structure during the evolution of the plastid from a green alga. While Photosystem II (PSII) composition is well conserved, Photosystem I (PSI) composition has undergone a dramatic reduction in accessory protein subunits...
May 31, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28618662/a-one-year-on-line-multi-site-observational-study-on-water-soluble-inorganic-ions-in-pm2-5-over-the-pearl-river-delta-region-china
#20
Jian Liu, Dui Wu, Shaojia Fan, Xia Mao, Huizhong Chen
As the significant components of PM2.5, almost all of previous studies on water-soluble inorganic ions (WSIIs) have been limited by the use of single sampling station, short sampling times or low temporal resolution. This paper focuses on analysing one-year (2012) observations of WSIIs at a regional central (RCEN) site, a coastal urban (CURB) site and a coastal rural (CRUR) site in the Pearl River Delta region. On average, secondary inorganic aerosols (SIA) were the most abundant component and accounted for over 80% of the total WSIIs...
June 10, 2017: Science of the Total Environment
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