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https://www.readbyqxmd.com/read/28822258/photochemical-oxidation-of-dimethylsulphide-to-dimethylsulphoxide-in-estuarine-and-coastal-waters
#1
Günther Uher, J Julian Pillans, Angela D Hatton, Robert C Upstill-Goddard
Dimethylsulphide (DMS) photo-oxidation and dimethylsulphoxide (DMSO) photoproduction were estimated in 26 laboratory irradiations of coastal samples from NE England (Tyne estuary) and W Scotland (Loch Linnhe and River Nant at Taynuilt). Pseudo-first order rate constants of DMS photo-oxidation (0.038 h(-1) to 0.345 h(-1)) and DMSO photo-production (0.017 h(-1) to 0.283 h(-1)) varied by one order of magnitude and were lowest in the coastal North Sea. Estuarine samples (salinity S < 30) had a mean DMSO yield of 96 ± 16% (n = 14), consistent with 1:1 M conversion via photosensitised oxidation by singlet oxygen...
August 11, 2017: Chemosphere
https://www.readbyqxmd.com/read/28821157/in-situ-formation-of-injectable-and-porous-heparin-based-hydrogel
#2
Meeichyn Goh, Younghee Kim, Kihak Gwon, Kiyoon Min, YoungMin Hwang, Giyoong Tae
In this study, by combining photopolymerization and particle leaching technique, in situ formation of porous hydrogel with pore interconnectivity was demonstrated in vivo upon subcutaneous injection into the back of mice as well as in vitro. A precursor solution containing thiolated heparin, PEG-diacrylate (PEG-DA), and gelatin microparticles (GMPs) as a fast dissolving porogen were photopolymerized by visible-light-initiated thiol-ene reaction with eosin Y (EY) as a photo initiator and triethanolamine (TEOA) as a co-initiator...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821033/novel-nitroaniline-cellulose-nanohybrids-nitro-radical-photo-release-and-its-antibacterial-action
#3
Prashant Chauhan, Ning Yan
In this study, carboxylated nanocrystalline cellulose is surface functionalized by a chromophoric nitro radical (NO) photodonor via covalent bonding. The resulting new photoactive nanohybrid material displays an effective photogeneration of NO radicals upon illumination by light. The release of NO radicals has been chemically detected by various spectroscopic techniques. The bactericidal activity of the novel nanohybrid is effectively demonstrated against both Gram positive (Staphylococcus aureus) and Gram negative (Pseudomonas aeruginosa) bacteria with light...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28820744/simulation-of-morphologically-structured-photo-thermal-neural-stimulation
#4
Y Weissler, N Farah, S Shoham
OBJECTIVE: Rational design of next-generation techniques for photo-thermal excitation requires the development of tools capable of modeling the effects of spatially- and temporally-dependent temperature distribution on cellular neuronal structures. APPROACH: We present a new computer simulation tool for predicting the effects of arbitrary spatiotemporally-structured photo-thermal stimulation on 3D, morphologically realistic neurons. The new simulation tool is based on interfacing two generic platforms, NEURON and MATLAB and is therefore suited for capturing different kinds of stimuli and neural models...
August 18, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28820602/intricate-resonant-raman-response-in-anisotropic-res2
#5
Amber McCreary, Jeffrey R Simpson, Yuanxi Wang, Daniel Rhodes, Kazunori Fujisawa, Luis Balicas, Madan Dubey, Vincent H Crespi, Mauricio Terrones, Angela R Hight Walker
The strong in-plane anisotropy of rhenium disulfide (ReS2) offers an additional physical parameter that can be tuned for advanced applications such as logic circuits, thin-film polarizers, and polarization-sensitive photodetectors. ReS2 also presents advantages for optoelectronics, as it is both a direct-gap semiconductor for few-layer thicknesses (unlike MoS2 or WS2) and stable in air (unlike black phosphorus). Raman spectroscopy is one of the most powerful characterization techniques to non-destructively and sensitively probe the fundamental photo-physics of a 2D material...
August 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28820598/methylene-blue-location-in-hydroperoxized-cardiolipin-monolayer-implication-in-membrane-photodegradation
#6
Rafael Maglia de Souza, Paulo Siani, Thaís F Schmidt, Rosangela Itri, Luis Gustavo Dias
We present molecular dynamics simulations of Cardiolipin (CL) and of a CL monohydroperoxized derivative (CLOOH) monolayers to investigate the initial steps of phospholipid oxidation induced by methylene blue (MB) photo-excitation under continuous illumination. We considered different MB atomic charge distributions to simulate MB electronic distribution in the singlet ground and triplet excited states. Simulation results allied to experimental data revealed that initial CL photooxidation probably occurs via type II mechanism, to produce lipid hydroperoxide by singlet oxygen attack to the alkyl chain unsaturations...
August 18, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28820595/vibronic-origin-of-the-qy-absorption-tail-of-bacteriochlorophyll-a-verified-by-fluorescence-excitation-spectroscopy-and-quantum-chemical-simulations
#7
Kristjan Leiger, Juha Matti Linnanto, Arvi Freiberg
The long-wavelength tail of the lowest-energy Qy singlet absorption band of bacteriochlorophyll a in triethylamine peaking at 768.6 nm was examined by means of fluorescence excitation spectroscopy at ambient temperature of 22±1°C. The tail, usually considered a Gaussian, is in fact weakening quasi-exponentially, being clearly evident as far as 940 nm, nearly 2400 cm(-1) (~12 kBT) away from the absorption peak. Quantum chemical simulations identified vibronic transitions from the thermally populated normal modes and their overtones in the ground electronic state as the origin of this tail...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28820580/enhanced-fluorescence-emission-and-singlet-oxygen-generation-of-photosensitizers-embedded-in-injectable-hydrogels-for-imaging-guided-photodynamic-cancer-therapy
#8
Liu-Yuan Xia, Xiaodong Zhang, Meng Cao, Zhan Chen, Fu-Gen Wu
Benefiting from their inherent localized and controlled release properties, hydrogels are ideal delivery systems for therapeutic drugs or nanoparticles. In particular, the applications of hydrogels for the delivery and release of photo-responsive drugs or nanoparticles are receiving increasing attention. However, the effect of the hydrogel matrix on the fluorescence emission and singlet oxygen generation efficiency of the embedded photosensitizers (PSs) has not been clarified. Herein, meso-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP) as a water-soluble PS is encapsulated into an injectable hydrogel formed by glycol chitosan and dibenzaldehyde-terminated telechelic poly(ethylene glycol)...
August 18, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28820218/photophysical-characterization-and-time-resolved-spectroscopy-of-a-anthradithiophene-dimer-exploring-the-role-of-conformation-in-singlet-fission
#9
Jacob C Dean, Ruomeng Zhang, Rawad K Hallani, Ryan D Pensack, Samuel N Sanders, Daniel G Oblinsky, Sean R Parkin, Luis M Campos, John E Anthony, Gregory D Scholes
Quantitative singlet fission has been observed for a variety of acene derivatives such as tetracene and pentacene, and efforts to extend the library of singlet fission compounds is of current interest. Preliminary calculations suggest anthradithiophenes exhibit significant exothermicity between the first optically-allowed singlet state, S1, and 2 × T1 with an energy difference of >5000 cm(-1). Given the fulfillment of this ingredient for singlet fission, here we investigate the singlet fission capability of a difluorinated anthradithiophene dimer (2ADT) covalently linked by a (dimethylsilyl)ethane bridge and derivatized by triisobutylsilylethynyl (TIBS) groups...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28820214/mediated-water-electrolysis-in-biphasic-systems
#10
Micheál D Scanlon, Pekka Peljo, Lucie Rivier, Heron Vrubel, Hubert H Girault
The concept of efficient electrolysis by linking photoelectrochemical biphasic H2 evolution and water oxidation processes in the cathodic and anodic compartments of an H-cell, respectively, is introduced. Overpotentials at the cathode and anode are minimised by incorporating light-driven elements into both biphasic reactions. The concepts viability is demonstrated by electrochemical H2 production from water splitting utilising a polarised water-organic interface in the cathodic compartment of a prototype H-cell...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28819291/a-single-molecule-assessment-of-the-protective-effect-of-dmso-against-dna-double-strand-breaks-induced-by-photo-and-%C3%AE-ray-irradiation-and-freezing
#11
Masami Noda, Yue Ma, Yuko Yoshikawa, Tadayuki Imanaka, Toshiaki Mori, Masakazu Furuta, Tatsuaki Tsuruyama, Kenichi Yoshikawa
Dimethyl sulfoxide (DMSO) is widely used as a cryoprotectant for organs, tissues, and cell suspension in storage. In addition, DMSO is known to be a useful free radical scavenger and a radio-protectant. To date, many in vitro assays using cultured cells have been performed for analysing the protective effect of DMSO against genomic DNA damage; however, currently it has been rather difficult to detect DNA double strand breaks (DSBs) in a quantitative manner. In the present study, we aimed to observe the extent of DNA damage by use of single molecular observation with a fluorescence microscope to evaluate DSBs induced by photo- and γ-ray-irradiation, or freeze/thawing in variable concentrations of DMSO...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818764/screening-of-biologically-important-zn-2-by-a-chemosensor-with-fluorescent-turn-on-off-mechanism
#12
Tanveer A Khan, Monika Sheoran, Venkata Nikhil Raj M, Surbhi Jain, Diksha Gupta, Sunil G Naik
Reported herein the synthesis, characterization and biologically important zinc ion binding propensity of a weakly fluorescent chemosensor, 4-methyl-2,6-bis((E)-(2-(4-phenylthiazol-2-yl)hydrazono)methyl)phenol (1). (1)H NMR spectroscopic titration experiment reveals the binding knack of 1 to the essential Zn(2+). The photo-physical studies of 1 exhibit an enhancement in the fluorescence by several folds upon binding with the zinc ions attributed to PET-off process, with a binding constant value of 5.22×10(3)M(-1)...
August 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28818020/preserving-self-theorizing-the-social-and-psychological-processes-of-living-with-parkinson-disease
#13
Terrie Vann-Ward, Janice M Morse, Kathy Charmaz
The purpose of this constructivist grounded theory article is to identify, explore, and theorize the social and psychological processes used by people with Parkinson disease. Analytic procedures generated the five-stage theory of Preserving self of people with Parkinson disease: (a) making sense of symptoms, (b) defining turning points, (c) experiencing identity dilemmas, (d) reconnecting the self, and (e) envisioning a future. Reminders of former selves and capabilities were painful; participants desperately sought normalcy...
June 2017: Qualitative Health Research
https://www.readbyqxmd.com/read/28817569/long-term-assessment-of-whale-shark-population-demography-and-connectivity-using-photo-identification-in-the-western-atlantic-ocean
#14
Jennifer A McKinney, Eric R Hoffmayer, Jason Holmberg, Rachel T Graham, William B Driggers, Rafael de la Parra-Venegas, Beatriz E Galván-Pastoriza, Steve Fox, Simon J Pierce, Alistair D M Dove
The predictable occurrence of whale sharks, Rhincodon typus, has been well documented in several areas. However, information relating to their migratory patterns, residency times and connectivity across broad spatial scales is limited. In the present study photo-identification data is used to describe whale shark population structure and connectivity among known aggregation sites within the Western Central Atlantic Ocean (WCA). From 1999 to 2015, 1,361 individuals were identified from four distinct areas: the Yucatan Peninsula, Mexico (n = 1,115); Honduras (n = 146); northern Gulf of Mexico, United States (n = 112), and Belize (n = 49)...
2017: PloS One
https://www.readbyqxmd.com/read/28817254/highly-001-textured-tetragonal-bifeo3-film-and-its-photoelectrochemical-behaviors-tuned-by-magnetic-field
#15
Haomin Xu, Yuanhua Lin, Takashi Harumoto, Ji Shi, Ce-Wen Nan
Highly (001)-textured BiFeO3 film in tetragonal phase (T-BFO) with a giant c/a ratio was firstly obtained on quartz/polycrystalline ITO substrate. Our results indicate that the polycrystalline ITO layer with small surface roughness is a critical point to control the growth of T-BFO structure. It should be ascribed to the fact that a Bi-rich phase interlayer (~5 nm) could be formed on ITO, which acted as a crystal seed layer and thus induced the growth of (001)-textured T-BFO structure. The observed weak room temperature ferromagnetism should be attributed to Fe valance change...
August 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28816311/hierarchical-core-shell-sio2-pda-biobr-microspheres-with-enhanced-visible-light-driven-photocatalytic-performance
#16
Shuai-Ru Zhu, Qi Qi, Wen-Na Zhao, Meng-Ke Wu, Yuan Fang, Kai Tao, Fei-Yan Yi, Lei Han
To explore catalysts combining highly accessible specific surface areas with low recombination of the photo-induced electron-hole pairs, a novel SiO2@PDA@BiOBr composite photocatalyst with a hierarchical core-shell structure was prepared by a facile solvothermal method. The catalyst shows a superior performance on photodegradation of Rhodamine B under visible light irradiation, especially for SiO2@PDA-2@BiOBr with the reactant kinetics constant (k = 0.0487 min(-1)). The enhanced photocatalytic performance of SiO2@PDA-2@BiOBr was ascribed to the decreased band-gap, higher surface area, and effectively photo-generated electron-hole pairs by the introduction of polydopamine (PDA)...
August 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28816047/light-independent-ionic-transport-in-inorganic-perovskite-and-ultra-stable-cs-based-perovskite-solar-cells
#17
Wenke Zhou, Yicheng Zhao, Xu Zhou, Rui Fu, Qi Li, Yao Zhao, Kaihui Liu, Dapeng Yu, Qing Zhao
Due to light-induced effects in CH3NH3-based perovskites, such as ion migration, defects formation and halide segregation, the degradation of CH3NH3-based perovskite solar cells under maximum power point is generally concerned. Here we demonstrated that the effect of light-enhanced ion migration in CH3NH3PbI3 can be eliminated by inorganic Cs substitution, leading to an ultra-stable perovskite solar cell. Quantitatively, the ion migration barrier for CH3NH3PbI3 is 0.62 eV under dark, larger than CsPbI2Br (0...
August 17, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28815776/a-photochemical-and-electrochemical-triggered-bis-hydrazone-switch
#18
Mónica A Gordillo, Mónica Soto-Monsalve, Christian C Carmona-Vargas, Gustavo Gutierrez, Richard F D'vries, Jean-Marie Lehn, Manuel N Chaur
Herein, we report the synthesis of a double hydrazone capable of undergoing photochemical E/Z isomerization through the imine double bonds. The bis(hydrazone) 1-E,E can be considered as a "two-arm" system in which the controlled movement of each arm is obtained by photo-modulation, making possible the appearance of two isolable metastable isomeric states 1-E,Z and 1-Z,Z. Such states are characterized by very specific structural, optical and electrochemical properties. The latter, allows the reversible return from either 1-E,Z or 1-Z,Z to the 1-E,E state...
August 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28815775/pet-switching-mechanism-of-a-napthalimide-derivative-with-its-solvatochromic-behaviour-an-experimental-and-theoretical-study-with-in-cell-investigations
#19
Dipti Singharoy, Sourav Chowdhury, Soumya Sundar Mati, Swadesh Ghosh, Krishnananda Chattopadhyay, Subhash Chandra Bhattacharya
The sole existence of t-bone shape napthalimide derivative [2-(2-aminoethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione] (NAP) which in turn gives rise to a PET mechanism, has been established using a combination of experimental and theoretical studies. In parallel an in vitro-in cell PET mechanism has also been shown. To understand the photo physics of NAP, solvent studies have been carried out in different solvents. In addition, theoretical calculations have been resorted to explain the spectroscopic properties through optimized structures...
August 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28815632/uniform-sized-neurosphere-mediated-motoneuron-differentiation-in-microwell-arrays
#20
Jong Min Lee, Joo Yoon Moon, Mohammed R Shaker, Woong Sun, Bong Geun Chung
We developed the photo-crosslinkable hydrogel microwell arrays for uniform-sized neurosphere-mediated motoneuron differentiation. Neural stem cells (NSCs) were obtained from embryonic cerebral cortex and spinal cord. To generate uniform-sized neurospheres in a homogeneous manner, the dissociated cells were cultured in the hydrogel microwell arrays for 3 days. Uniform-sized neurospheres harvested from microwell arrays were replated into laminin-coated a two-dimensional (2D) substrate. In parallel, uniform-sized neurospheres cultured in microwell arrays were encapsulated by photocrosslinkable gelatin methacrylate (GelMA) hydrogels in a three-dimensional (3D) manner...
August 16, 2017: Electrophoresis
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