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https://www.readbyqxmd.com/read/28426213/role-of-mediator-and-effects-of-temperature-on-ortho-c-n-bond-fusion-reactions-of-aniline-using-ruthenium-templates-isolation-and-characterization-of-new-ruthenium-complexes-of-the-in-situ-generated-ligands
#1
Suman K Roy, Debabrata Sengupta, Santi Prasad Rath, Tanushri Saha, Subhas Samanta, Sreebrata Goswami
In this work, ortho-C-N bond fusion reactions of aniline are followed by the use of two different ruthenium mediators. Reaction of aniline with [Ru(III)(terpy)Cl3] (terpy = 2,2':6',2″-terpyridine) resulted in a trans bis-aniline ruthenium(II) complex [1](+) which upon oxidation with H2O2 produced compound [2](+) of a bidentate ligand, N-phenyl-1,2-benzoquinonediimine, due to an oxidative ortho-C-N bond fusion reaction. Complex [1](+) and aniline (neat) at 185 °C produced a bis-chelated ruthenium complex (3)...
April 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28406298/reaction-of-aniline-with-singlet-oxygen-o2-1-%C3%AE-g
#2
Jomana Al-Nu'airat, Mohammednoor K Altarawneh, Xiangpeng Gao, Phillip R Westmoreland, Bogdan Z Dlugogorski
Dissolved organic matter (DOM) acts as an effective photochemical sensitiser that produces the singlet delta state of molecular oxygen (O2 1Δg), a powerful oxidiser that removes aniline from aqueous solutions. However, the exact mode of this reaction, the para to ortho-iminobenzoquinone ratio, and the selectivity of one over the other remain largely speculative. This contribution resolves these uncertainties. We report, for the first time, a comprehensive mechanistic and kinetic account of the oxidation of aniline with the singlet delta oxygen using B3LYP and M06 functionals in both gas and aqueous phases...
April 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28358500/molecular-mechanism-of-dioxin-formation-from-chlorophenol-based-on-electron-paramagnetic-resonance-spectroscopy
#3
Li Li Yang, Guorui Liu, Minghui Zheng, Yuyang Zhao, Rong Jin, Xiaolin Wu, Yang Xu
Few studies have investigated the free radical intermediates involved in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from chlorophenol. This study clarified the reaction pathways during thermochemical formation of PCDDs from 2,3,6-trichlorophenol (TCP) over a Cu(II)O/silica matrix, which was used to simulate fly ash, at 298-523 K. The reaction was studied using electron paramagnetic resonance (EPR) spectroscopy and theoretical calculations. In situ EPR indicated the TCP radical (TCPR) formed by hydrogen abstraction of TCP...
March 30, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28346278/effects-of-myopic-orthokeratology-on-visual-performance-and-optical-quality
#4
Guihua Liu, Zhi Chen, Feng Xue, Jing Li, Mi Tian, Xingtao Zhou, Ruihua Wei
OBJECTIVES: To analyze the changes in visual performance and optical quality after orthokeratology (ortho-k) treatment and its correlation with the magnitude of lens decentration and the diameter of treatment zone (TxZ). METHODS: A prospective study was conducted in 27 eyes of 27 patients wearing ortho-k contact lens. Area under log contrast sensitivity function (AULCSF), modulation transfer function cutoff values (MTFcutoff), Strehl ratio (SR), and objective scattering index (OSI) were measured and compared before and 1 month after ortho-k lens treatment...
March 24, 2017: Eye & Contact Lens
https://www.readbyqxmd.com/read/28337465/inflammatory-response-and-barrier-dysfunction-by-different-e-cigarette-flavoring-chemicals-identified-by-gas-chromatography-mass-spectrometry-in-e-liquids-and-e-vapors-on-human-lung-epithelial-cells-and-fibroblasts
#5
Janice Gerloff, Isaac K Sundar, Robert Freter, Emily R Sekera, Alan E Friedman, Risa Robinson, Todd Pagano, Irfan Rahman
Recent studies suggest that electronic cigarette (e-cig) flavors can be harmful to lung tissue by imposing oxidative stress and inflammatory responses. The potential inflammatory response by lung epithelial cells and fibroblasts exposed to e-cig flavoring chemicals in addition to other risk-anticipated flavor enhancers inhaled by e-cig users is not known. The goal of this study was to evaluate the release of the proinflammatory cytokine (interleukin-8 [IL-8]) and epithelial barrier function in response to different e-cig flavoring chemicals identified in various e-cig e-liquid flavorings and vapors by chemical characterization using gas chromatography-mass spectrometry analysis...
March 1, 2017: Applied in Vitro Toxicology
https://www.readbyqxmd.com/read/28330347/the-interaction-of-no-x-2-%C3%AE-with-h2-ab-initio-potential-energy-surfaces-and-bound-states
#6
Jacek Kłos, Qianli Ma, Millard H Alexander, Paul J Dagdigian
We determine from first principles two sets of four-dimensional diabatic potential energy surfaces (PES's) for the interaction of NO(X(2)Π) with H2, under the assumption of fixed NO and H2 bond distances. The first set of PES's was computed with the explicitly correlated multi-reference configuration interaction method [MRCISD-F12 + Q(Davidson)], and the second set with an explicitly correlated, coupled-cluster method [RCCSD(T)-F12a] with the geometry scan limited to geometries possessing a plane of symmetry...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28316808/crystal-structure-of-the-monoclinic-phase-phase-iv-of-bis-tetra-methyl-ammonium-tetra-chlorido-cuprate-ii
#7
Gorgui Awa Seck, Libasse Diop, Allen G Oliver
The crystal structure of the low-temperature monoclinic phase of the title compound, [(CH3)4N]2[CuCl4], was determined at 120 K. The structure of the room-temperature phase has been determined in the ortho-rhom-bic space group Pmcm [Morosin & Lingafelter (1961 ▸). J. Phys. Chem. 50-51; Clay et al. (1975 ▸). Acta Cryst. B31 289-290]. The asymmetric unit consists of one discrete tetra-chlorido-cuprate anion with a distorted tetra-hedral geometry and two tetra-methyl-ammonium cations. In the crystal, the cations and the anions are linked via weak C-H⋯Cl hydrogen bonds...
March 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28316195/-analysis-of-corneal-complications-in-children-wearing-orthokeratology-lenses-at-night
#8
C X Miao, X Y Xu, H Zhang
Objective: To explore the characteristics, prognoses and corneal complications of children wearing orthokeratology lenses (Ortho-K) at night. Methods: Retrospective case analysis. A total of 113 cases (219 eyes) wore Ortho-K for myopia at night, including 7 cases with unilateral glass wear. The average age was (11.5±2.0) years old. The myopia ranged from -1.00 D to -9.00 D in all eyes and from -2.00 D to -4.00 D in 157 of them. Examinations were performed before lens wearing, at 1 hour, the next morning, 2 days, 3 days, 1 week and 2 weeks after lens wearing, and thereafter once a month...
March 11, 2017: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
https://www.readbyqxmd.com/read/28299841/fluorinated-unsymmetrical-n-n-diaryl-imidazolium-salts-new-functionalized-nhc-ligand-precursors
#9
Sergey N Osipov, Maria A Zotova, Salekh M Masoud, Artur K Mailyan, Ivan V Ananyev, Sergey E Nefedov, Andrey F Asachenko, Maxim A Topchiy
An efficient and scaled-up synthesis of the imidazol-2-ylidene-based unsymmetrical NHC precursors bearing sterically demanding hexafluoroisopropylalkoxy-group [(CF3)2(OR)C-] in ortho-position of N-aryl substituent was developed. The key step of the method involved transformation of Mes-substituted oxazolinium tetrafluoroborate salt via the reaction with the corresponding binucleophilic fluoroalkyl substituted aniline. The subsequent post-modification of the resulting hydroxyl-containing salt via simple one step O-alkylation protocol provided access to a new family of fluorinated NHC precursors...
March 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28298110/near-infrared-overtone-voh-2-%C3%A2-0-spectroscopy-of-ne-h2o-clusters
#10
Michael P Ziemkiewicz, Christian Pluetzer, Michael Wojcik, Jérôme Loreau, Ad van der Avoird, David J Nesbitt
Vibrationally state selective overtone spectroscopy and dynamics of weakly bound Ne-H2O complexes (D0((para)) = 31.67 cm(-1), D0((ortho)) = 34.66 cm(-1)) are reported for the first time, based on near infrared excitation of van der Waals cluster bands correlating with vOH = 2 ← 0 overtone transitions (|02(-)⟩←|00(+)⟩ and |02(+)⟩←|00(+)⟩) out of the ortho (101) and para (000) internal rotor states of the H2O moiety. Quantum theoretical calculations for nuclear motion on a high level ab initio potential energy surface (CCSD(T)/VnZ-f12 (n = 3,4), corrected for basis set superposition error and extrapolated to the complete basis set limit) are employed for assignment of Σ←Σ,Π←Σ, and Σ←Π infrared bands in the overtone spectra, where Σ(K = 0) and Π (K = 1) represent approximate projections (K) of the body angular momentum along the Ne-H2O internuclear axis...
March 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28291200/-stabilizing-effect-of-orthokeratology-lenses-ten-year-follow-up-results
#11
E P Tarutta, T Yu Verzhanskaya
The global prevalence of myopia in adults varies between 20-50% in Europe and the US and 60-90% in Asian countries. According to WHO, myopia is one of the five leading causes of blindness and low vision in the world. Prevention or deceleration of myopia progression is an important public health problem. In recent years, orthokeratology (ortho-k) contact lenses worn at night have been found effective in slowing down the progression of myopia, however, the follow-up period in related studies is no longer than five years...
2017: Vestnik Oftalmologii
https://www.readbyqxmd.com/read/28287790/cocaine-self-administration-in-male-and-female-rats-perinatally-exposed-to-pcbs-evaluating-drug-use-in-an-animal-model-of-environmental-contaminant-exposure
#12
Mellessa M Miller, Abby E Meyer, Jenna L N Sprowles, Helen J K Sable
Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants known to adversely impact human health. Ortho-substituted PCBs affect the nervous system, including the brain dopaminergic system. The reinforcing effects of psychostimulants are typically modulated via the dopaminergic system, so this study used a preclinical (i.e., rodent) model to evaluate whether developmental contaminant exposure altered intravenous self-administration (IV SA) for the psychostimulant cocaine. Long-Evans rats were perinatally exposed to 6 or 3 mg/kg/day of PCBs throughout gestation and lactation and compared with nonexposed controls...
April 2017: Experimental and Clinical Psychopharmacology
https://www.readbyqxmd.com/read/28287419/bimolecular-rate-constants-for-fad-dependent-glucose-dehydrogenase-from-aspergillus-terreus-and-organic-electron-acceptors
#13
Nozomu Tsuruoka, Takuya Sadakane, Rika Hayashi, Seiya Tsujimura
The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus...
March 10, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28278579/ph-activated-nano-amorphous-calcium-phosphate-based-cement-to-reduce-dental-enamel-demineralization
#14
Mary A S Melo, Michael D Weir, Vanara F Passos, Michael Powers, Hockin H K Xu
Enamel demineralization is destructive, esthetically compromised, and costly complications for orthodontic patients. Nano-sized amorphous calcium phosphate (NACP) has been explored to address this challenge. The 20% NACP-loaded ortho-cement notably exhibited favorable behavior on reducing demineralization of enamel around brackets in a caries model designed to simulate the carious attack. The 20% NACP-loaded ortho-cement markedly promotes higher calcium and phosphate release at a low pH, and the mineral loss was almost two fold lower and carious lesion depth decreased the by 1/3...
February 21, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28254587/activity-of-human-kallikrein-related-peptidase-6-klk6-on-substrates-containing-sequences-of-basic-amino-acids-is-it-a-processing-protease
#15
Roberta N Silva, Lilian C G Oliveira, Carolina B Parise, Juliana R Oliveira, Beatrice Severino, Angela Corvino, Paola di Vaio, Piero A Temussi, Giuseppe Caliendo, Vincenzo Santagada, Luiz Juliano, Maria A Juliano
Human kallikrein 6 (KLK6) is highly expressed in the central nervous system and with elevated level in demyelinating disease. KLK6 has a very restricted specificity for arginine (R) and hydrolyses myelin basic protein, protein activator receptors and human ionotropic glutamate receptor subunits. Here we report a previously unreported activity of KLK6 on peptides containing clusters of basic amino acids, as in synthetic fluorogenic peptidyl-Arg-7-amino-4-carbamoylmethylcoumarin (peptidyl-ACC) peptides and FRET peptides in the format of Abz-peptidyl-Q-EDDnp (where Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-(2,4-dinitrophenyl) ethylenediamine), in which pairs or sequences of basic amino acids (R or K) were introduced...
February 28, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28253404/protective-role-of-orthokeratology-in-reducing-risk-of-rapid-axial-elongation-a-reanalysis-of-data-from-the-romio-and-to-see-studies
#16
Pauline Cho, Sin-Wan Cheung
Purpose: To determine the relative risk of rapid progression and number needed to treat (NNT) in younger and older children using combined data from the retardation of myopia in orthokeratology (ROMIO) and toric orthokeratology-slowing eye elongation (TO-SEE) studies. Methods: Data from 136 subjects of two studies, ROMIO and TO-SEE, were retrieved (72 orthokeratology [ortho-k]: 37 ROMIO, 35 TO-SEE; 64 control: 41 ROMIO, 23 TO-SEE) and the myopia control effect on younger (6-8 years) and older (9-12 years) subjects evaluated...
March 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28249428/hydrogen-bond-induced-hf-elimination-from-photoionized-fluorophenol-dimers-in-the-gas-phase
#17
Piyali Chatterjee, Arup K Ghosh, Tapas Chakraborty
In this paper, we report finding of a remarkable chemical effect of hydrogen bonding, elimination of hydrogen fluoride (HF) from the hydrogen bonded dimers of 2-fluorophenol (2-FP) and 3-fluorophenol (3-FP), in a supersonic jet expansion upon multi-photon ionization using 4th harmonic wavelength (266 nm) of a Q-switched Nd:YAG laser, and the reaction has been probed by time-of-flight mass spectrometry. No HF elimination is observed to occur by such means from the monomer of 3-FP, but it occurs with a small yield from the monomer of 2-FP...
February 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28228030/anion-photoelectron-spectroscopy-of-deprotonated-ortho-meta-and-para-methylphenol
#18
Daniel J Nelson, Wilson K Gichuhi, Elisa M Miller, Julia H Lehman, W Carl Lineberger
The anion photoelectron spectra of ortho-, meta-, and para-methylphenoxide, as well as methyl deprotonated meta-methylphenol, were measured. Using the Slow Electron Velocity Map Imaging technique, the Electron Affinities (EAs) of the o-, m-, and p-methylphenoxyl radicals were measured as follows: 2.1991±0.0014, 2.2177±0.0014, and 2.1199±0.0014 eV, respectively. The EA of m-methylenephenol was also obtained, 1.024±0.008 eV. In all four cases, the dominant vibrational progressions observed are due to several ring distortion vibrational normal modes that were activated upon photodetachment, leading to vibrational progressions spaced by ∼500 cm(-1)...
February 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28224791/copper-catalyzed-tandem-o-arylation-oxidative-cross-coupling-synthesis-of-chromone-fused-pyrazoles
#19
Owk Obulesu, K Harish Babu, Jagadeesh Babu Nanubolu, Surisetti Suresh
Intermolecular tandem copper-catalyzed O-arylation-oxidative acylation (cross dehydrogenative coupling-CDC) has been developed under air as an oxidant. The reaction between 2,4-dihydro-3H-pyrazol-3-ones and ortho-halo aryl carboxaldehydes furnished the corresponding chromone fused pyrazoles, in a straightforward manner. The synthetic utility of the presented tandem catalysis has been demonstrated with the synthesis of an A2-subtype selective adenosine receptor antagonist in only two steps.
March 7, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28217358/crystal-structure-of-chlorido-bis-1-2-5-6-%C3%AE-cyclo-octa-1-5-diene-iridium-i
#20
A K Fazlur Rahman, Miles Wilklow-Marnell, William W Brennessel, William D Jones
The title complex, [IrCl(C8H12)2], was synthesized directly from the reaction of IrCl3·3H2O with a large excess of cod (cod = cyclo-octa-1,5-diene) in alcoholic solvent. Large yellow needles were obtained by the slow cooling of a hot solution. Based on the positions of the chloride ligand and the mid-points of the four C=C bonds, the mol-ecule adopts a five-coordinate geometry that is midway between square pyramidal and trigonal bipyramidal. The material crystallizes in the ortho-rhom-bic space group Pbca with one mol-ecule per asymmetric unit in a general position and shows no significant inter-molecular inter-actions...
February 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
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