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Ortho k

Leigh J Sowerby, Luke Rudmik
OBJECTIVE: Nasopharyngoscopes are an essential instrument to otolaryngologists; reprocessing them in a high-value manner is paramount. Although several different techniques for reprocessing exist, all methods yield similar effectiveness. Given equivalent effectiveness outcomes, a cost analysis of four nasopharyngoscope reprocessing techniques was performed. STUDY DESIGN: Cost-minimization analysis. METHODS: Four techniques were evaluated: 1) an automated reprocessor using peracetic acid (Steris System 1; Steris Canada Inc...
August 16, 2017: Laryngoscope
Lizhen Fang, Tyler G Saint-Denis, Buck L H Taylor, Seth Ahlquist, Kai Hong, SaiSai Liu, LiLi Han, K N Houk, Jin-Quan Yu
A conformationally flexible template for the meta-C-H olefination of benzoic acids was designed through both experimental and computational efforts. The newly designed template favors a silver-palladium heterodimer low barrier transition state, and demonstrates that it is feasible to lengthen templates so as to achieve meta-selectivity when the distance between the functional handle of the native substrate and target C-H bond decreases. Analysis of the ortho-, meta-, and para-C-H cleavage transition states determined that the new template conformation optimizes the interaction between the nitrile and palladium-silver dimer in the meta-transition state, enabling palladium to cleave meta-C-H bonds with moderate-to-good yields and generally high regioselectivity...
July 27, 2017: Journal of the American Chemical Society
Perruchon Chiara, Vasileiadis Sotirios, Rousidou Constantina, Papadopoulou S Evangelia, Tanou Georgia, Samiotaki Martina, Garagounis Constantinos, Molassiotis Athanassios, Papadopoulou K Kalliope, Karpouzas G Dimitrios
Ortho-phenylphenol (OPP) is a fungicide contained in agro-industrial effluents produced by fruit-packaging plants. Within the frame of developing bio-strategies to detoxify these effluents, an OPP-degrading Sphingomonas haloaromaticamans strain was isolated. Proteins/genes with a putative catabolic role and bacterium adaptation mechanisms during OPP degradation were identified via genomic and proteomic analysis. Transcription analysis of all putative catabolic genes established their role in the metabolism of OPP...
July 25, 2017: Scientific Reports
Zhi Chen, Feng Xue, Jiaqi Zhou, Xiaomei Qu, Xingtao Zhou
SIGNIFICANCE: Lens decentration is common and unavoidable to some extent during ortho-k treatment. By using a simplified method, we are able to predict the magnitude and direction of ortho-k lens decentration, which provides useful insights in screening for ideal ortho-k candidates and to make a quick decision when decentration happens. PURPOSE: The aim of this study was to investigate the influence of corneal elevation asymmetry on ortho-k lens decentration. METHODS: Thirty-six eyes of 36 subjects were fitted with four-curve reverse geometry ortho-k contact lenses...
July 24, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Venkata A K Adiraju, Caleb D Martin
The reactions of pentaphenylborole with pyridines with a pendent aryl group in the 2-position, specifically 2-phenylpyridine and 2,2'-bipyridine, readily afforded adducts. Upon thermolysis, the adducts converted to ortho C-H addition products with the two substituents introduced onto the diene on the boracyclic carbon atoms adjacent to boron in a syn fashion. Photolysis of the syn 2-phenypyridine product led to isomerization to the anti conformer which did not readily occur for the 2,2'-bipyridine complex. Such C-H bond reactivity is uncommon for main group elements and provides insight into methodologies to access boron frameworks...
July 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Moritz Klein, Matthias W Laschke, Joerg H Holstein, Tina Histing, Tim Pohlemann, Michael Menger, Patric Garcia
Despite the growing knowledge on the mechanisms of fracture healing, bone defects often do not heal in a timely manner. Clinically, tricalcium phosphate (Ca-P) bone substitutes are used to fill bone defects and promote bone healing. However, the degradation rate of these implants is often too slow for sufficient bone replacement. The use of calcium phosphate material with the crystalline phase Ca10 [K/Na](PO4)7 containing different amounts of di- and metaphosphates may overcome this problem, because these materials show an accelerated degradation...
July 10, 2017: Biomedical Materials
Thomas Vanfleteren, Tomas Földes, Michel Herman, Jacques Liévin, Jérôme Loreau, Laurent H Coudert
We have used continuous-wave cavity ring-down spectroscopy to record the spectrum of H2O-Ar in the 2OH excitation range of H2O. 24 sub-bands have been observed. Their rotational structure (Trot = 12 K) is analyzed and the lines are fitted separately for ortho and para species together with microwave and far infrared data from the literature, with a unitless standard deviation σ=0.98 and 1.31, respectively. Their vibrational analysis is supported by a theoretical input based on an intramolecular potential energy surface obtained through ab initio calculations and computation of the rotational energy of sub-states of the complex with the water monomer in excited vibrational states up to the first hexad...
July 7, 2017: Journal of Chemical Physics
Guilherme Thiesen, B F Gribel, M P M Freitas, D R Oliver, K B Kim
OBJECTIVES: The aim of this study was to evaluate the characteristics affecting different intensities of mandibular asymmetry in skeletal Class II adults using three-dimensional images. This study is clinically relevant since it allows professionals to evaluate the morphological components related to these deformities and more carefully obtain correct diagnosis and treatment plan for such patients. METHODS: Cone-beam computed tomography data of 120 Class II patients (40 with relative symmetry, 40 with moderate asymmetry, and 40 with severe asymmetry) were imported to SimPlant Ortho Pro(®) 2...
June 30, 2017: Journal of Orofacial Orthopedics, Fortschritte der Kieferorthopädie
Stefan Aichhorn, Raphael Bigler, Eddie L Myers, Varinder K Aggarwal
Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1'-benzylidene insertion into the C-B bond. The reaction occurs by a SN2' elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatized intermediate, which undergoes a Lewis-acid catalyzed 1,3-borotropic shift to afford the boronic ester products in high yield and with excellent enantiospecificity...
July 19, 2017: Journal of the American Chemical Society
Graham de Ruiter, Kurtis M Carsch, Michael K Takase, Theodor Agapie
A series of tetranuclear [LM3(HFArPz)3OM'][OTf]2 (M, M' = Fe or Mn) clusters that displays 3-(2-fluorophenyl)pyrazolate (HFArPz) as bridging ligand is reported. With these complexes manganese is demonstrated to facilitate C(sp2)-F bond oxygenation via a putative terminal metal-oxo species. Moreover, the presence of both ortho C(sp2)-H and C(sp2)-F bonds in proximity provides an opportunity to investigate the selectivity of intramolecular C(sp2)-X bond oxygenation (X = H or F) in these isostructural compounds...
June 28, 2017: Chemistry: a European Journal
Yansong Ma, Ning Zhang, Michael D Weir, Yuxing Bai, Hockin H K Xu
OBJECTIVES: White spot lesions due to biofilm acid-induced enamel demineralization are prevalent in orthodontic treatments. The aim of this study was to develop a novel bioactive multifunctional cement with protein-repellent, antibacterial and remineralizing capabilities, and investigate the effects on enamel hardness and lesion depth in vitro for the first time. MATERIALS AND METHODS: 2-Methacryloyloxyethyl phosphorylcholine (MPC), dimethylaminohexadecyl methacrylate (DMAHDM), and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into a resin-modified glass ionomer (RMGI)...
June 20, 2017: Journal of Dentistry
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
Wycliffe K Kipnusu, Mohamed Elsayed, Reinhard Krause-Rehberg, Friedrich Kremer
Glassy dynamics of polymethylphenylsiloxane (PMPS) is studied by broadband dielectric spectroscopy in one-dimensional (1D) and two-dimensional (2D) nanometric confinement; the former is realized in thin polymer layers having thicknesses down to 5 nm, and the latter in unidirectional (thickness 50 μm) nanopores with diameters varying between 4 and 8 nm. Based on the dielectric measurements carried out in a broad spectral range at widely varying temperatures, glassy dynamics is analyzed in detail in 1D and in 2D confinements with the following results: (i) the segmental dynamics (dynamic glass transition) of PMPS in 1D confinement down to thicknesses of 5 nm is identical to the bulk in the mean relaxation rate and the width of the relaxation time distribution function; (ii) additionally a well separated surface induced relaxation is observed, being assigned to adsorption and desorption processes of polymer segments with the solid interface; (iii) in 2D confinement with native inner pore walls, the segmental dynamics shows a confinement effect, i...
May 28, 2017: Journal of Chemical Physics
Carson Wiethan, Christopher M Lavoie, Andrey Borzenko, Jillian S K Clark, Helio G Bonacorso, Mark Stradiotto
The nickel-catalyzed cyclization of in situ generated ortho-chlorobenzophenone hydrazone derivatives, to afford 3-(hetero)aryl-1H-indazoles, is documented for the first time. The product 1H-indazoles can be transformed subsequently in a one-pot procedure into 1,3-di(hetero)aryl-1H-indazoles via copper-catalyzed N-arylation with (hetero)aryl bromides.
June 14, 2017: Organic & Biomolecular Chemistry
A I Adjieufack, I M Ndassa, I Patouossa, J K Mbadcam, V S Safont, M Oliva, J Andrés
In this work we report on the progress that has been made towards gaining an understanding of the molecular mechanism of 1,3-dipolar cycloadditions using the bonding evolution theory (BET). A detailed analysis of the flow of electron density along the reaction pathway of the formal 1,3-dipolar cycloaddition reaction between cyclic nitrones (pyrroline-1-oxide and 2,3,4,5-tetrahydropyridine-1-oxide) and ethyl acrylate, as a case study, allowed the nature of the molecular mechanisms to be characterized. The present study provides a deep insight into the reaction mechanism, based on the electron density rearrangements given by the structural stability domains, and their connection with the bond breaking/forming processes along the reaction pathway...
May 31, 2017: Physical Chemistry Chemical Physics: PCCP
Junzhi Liu, Ji Ma, Ke Zhang, Prince Ravat, Peter Machata, Stanislav Avdoshenko, Felix Hennersdorf, Hartmut Komber, Wojciech Pisula, Jan J Weigand, Alexey A Popov, Reinhard Berger, Klaus Müllen, Xinliang Feng
Synthesis of antiaromatic polycyclic hydrocarbons (PHs) is challenging because the high energy of their highest occupied molecular orbital and low energy of their lowest unoccupied molecular orbital cause them to be reactive and unstable. In this work, two large antiaromatic acene analogues, namely, cyclopenta[pqr]indeno[2,1,7-ijk]tetraphene (CIT, 1a) and cyclopenta[pqr]indeno[7,1,2-cde]picene (CIP, 1b), as well as a curved antiaromatic molecule with 48 π-electrons, dibenzo[a,c]diindeno[7,1,2-fgh:7',1',2'-mno]phenanthro[9,10-k]tetraphene (DPT, 1c), are synthesized on the basis of the corona of indeno[1,2-b]fluorene...
June 7, 2017: Journal of the American Chemical Society
Anton Yu Shabalin, Nicolay Yu Adonin, Vadim V Bardin
Borates M[C6F5BF3] (M = K, Li, Bu4N) react with organolithium compounds, RLi (R = Me, Bu, Ph), in 1,2-dimethoxyethane or diglyme to give M[4-RC6F4BF3] and M[2-RC6F4BF3]. When R is Me or Bu, the nucleophilic substitution of the fluorine atom at the para position to boron is the predominant route. When R = Ph, the ratio M[4-RC6F4BF3]/M[2-RC6F4BF3] is ca. 1:1. Substitution of the fluorine atom at the ortho position to boron is solely caused by the coordination of RLi via the lithium atom with the fluorine atoms of the BF3 group...
2017: Beilstein Journal of Organic Chemistry
Anisha Purkait, Subhra Kanti Roy, Hemant Kumar Srivastava, Chandan K Jana
Hydrogen bond assisted ortho-selective C(sp(2))-H amination of nitrosoarenes and subsequent α-C(sp(3))-H functionalization of aliphatic amines is achieved under metal-free conditions. The annulation of nitrosoarenes and 2-hydroxy-C-nitroso compounds with N-heterocycles provides a facile excess to a wide range of biologically relevant ring-fused benzimidazoles and structurally novel polycyclic imidazoles, respectively. Nucleophilic aromatic hydrogen substitution (SNArH) was found to be preferred over classical SNAr reaction during the C(sp(2))-H amination of halogenated nitrosoarenes...
May 9, 2017: Organic Letters
Holm Petzold, Paul Djomgoue, Gerald Hörner, Silvio Heider, Charles Lochenie, Birgit Weber, Tobias Rüffer, Dieter Schaarschmidt
Fe(2+) spin crossover complexes [Fe(L)2](2+) (L = 2-(6-R(1)-pyridin-2-yl)-1,10-phenanthroline with R(1) = H, methoxy, bromo, -(1H-pyrazol-1-yl) or L = 2-(3-methoxy-pyridin-2-yl)-1,10-phenanthroline) were prepared. These air stable and durable complexes show SCO behaviour with very different transition temperatures T1/2 ranging from 130 K to 600 K depending on the substitution pattern. The use of (1)H NMR spectroscopy to elucidate the thermodynamics and kinetics of SCO in a solution of this series is described in detail...
May 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Safwan Aroua, Tanya K Todorova, Paul Hommes, Lise-Marie Chamoreau, Hans-Ulrich Reissig, Victor Mougel, Marc Fontecave
Terpyridine ligands are widely used in chemistry and material sciences owing to their ability to form stable molecular complexes with a large variety of metal ions. In that context, variations of the substituents on the terpyridine ligand allow modulation of the material properties. Applying the Stille cross-coupling reaction, we prepared with good yields a new series of terpyridine ligands possessing quinoline-type moieties in ortho, meta, and para positions and dimethylamino substituents at central or distal positions...
April 25, 2017: Inorganic Chemistry
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