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223034

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Luis Felipe J Schneider et al.
Dental materials : official publication of the Academy of Dental Materials, 24(9), 1169-1177 (2008-03-08)
To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD...
Miguel G Neumann et al.
Dental materials : official publication of the Academy of Dental Materials, 22(6), 576-584 (2005-11-18)
To evaluate the efficiency of the photopolymerization of dental resins it is necessary to know to what extent the light emitted by the light curing units is absorbed by the photoinitiators. On the other hand, the efficiency of the absorbed...
Atsushi Kameyama et al.
Lasers in medical science, 26(3), 279-283 (2011-02-24)
The purpose of this study was to evaluate whether a Gallium Nitride (GaN) -based violet laser diode (VLM500) could be used as a light source for light-cured dental resins. Three experimental unfilled resins containing different photoinitiators (camphorquinone, CQ; phenyl propanedione...
Igor Busygin et al.
The Journal of organic chemistry, 73(17), 6559-6569 (2008-08-08)
Structures and conformational behavior of several cinchona alkaloid O-ethers in the solid state (X-ray), in solution (NMR and DFT), and in the gas phase (DFT) were investigated. In the crystal, O-phenylcinchonidine adopts the Open(3) conformation similar to cinchonidine, whereas the...
Luis Felipe J Schneider et al.
Dental materials : official publication of the Academy of Dental Materials, 25(5), 566-572 (2008-12-30)
Stress development during the polymerization process continues to be a major factor that limits predictability and longevity of resin composite restorations. This study evaluated the effect of the photoinitiator type on the maximum rate of polymerization (R(p)(max)), stress development (final...
Igor Busygin et al.
Journal of the American Chemical Society, 131(12), 4449-4462 (2009-03-06)
Assessing the origin of asymmetric induction in heterogeneously catalyzed hydrogenation is a challenging task. In this work, hydrogenation of a chiral compound, (R)-1-hydroxy-1-phenyl-2-propanone [(R)-PAC], in toluene over cinchonidine modified and unmodified Pt/Al(2)O(3) was studied. To reveal the detailed reaction mechanism...
Erik Asmussen et al.
Acta odontologica Scandinavica, 60(3), 146-150 (2002-08-09)
A slow contraction may result in reduced gap formation when a restorative resin polymerizes in a dental cavity. It was the aim in the present work to investigate the rate of contraction in relation to composition of experimental light-curing resin...
I Stipani et al.
Archives of biochemistry and biophysics, 331(1), 48-54 (1996-07-01)
The effect of arginine-specific reagents on the function of the purified and reconstituted oxoglutarate carrier protein of the inner mitochondrial membrane has been investigated. The alpha-dicarbonyl reagents 2,3-butanedione, 2,3-pentanedione, 2,3- and 3,4-hexanedione, 1-phenyl-1,2-propanedione, phenylglyoxal, and phenylglyoxal derivatives caused a concentration-dependent...
A Ogunyinka et al.
Dental materials : official publication of the Academy of Dental Materials, 23(7), 807-813 (2006-08-18)
The effect of photoinitiator and co-initiator chemistry on the setting reaction and degree of conversion of dental resin-based composites (RBCs) has rarely been determined explicitly. This work examines the effect of type and concentration of photoinitiator and co-initiator on the...
William Cunha Brandt et al.
Journal of dentistry, 39(6), 438-447 (2011-04-23)
The aim of this study was to evaluate the degree of conversion (DC), rate of polymerization (R(p)(max)), Knoop hardness (KHN) and bond strength between tooth/restoration of composite resins containing different photo-initiators photo-activated by different light-curing units (LCUs). A mixture of...
Marcello G Trevisan et al.
Talanta, 75(4), 1021-1027 (2008-07-01)
Fourier transform mid-infrared spectroscopy (FT-MIR) coupled with a homemade attenuated total reflectance (ATR) flow-cell was used for on-line monitoring of a biotransformation reaction. The reaction was also monitored off-line by gas chromatography-mass spectrometry (GC-MS) enabling to establish a multivariate model...
Luis Felipe J Schneider et al.
Dental materials : official publication of the Academy of Dental Materials, 25(3), 369-375 (2008-10-14)
To evaluate the effect of amine ratio (ethyl 4-dimethylaminobenzoate, EDMAB) on the maximum rate of polymerization (R(p)(max)), degree of conversion (DC), Knoop hardness (KH), water sorption (Wsp), water solubility (Wsl) and color changes (DeltaE) over time of resin composites formulated...
Jae-Seong Sim et al.
Journal of dentistry, 40(10), 836-842 (2012-07-10)
Recently the colour stability of composite resins has been an issue due to the emphasis on the aesthetics of restored teeth. The purpose of the present study was to investigate how dual-peak LED units affect the polymerization of coinitiator-containing composite...
B Toukoniitty et al.
Ultrasonics sonochemistry, 13(1), 68-75 (2005-10-15)
The enantioselective hydrogenation of 1-phenyl-1,2-propanedione was carried out over Pt/Al2O3, Pt/SiO2, Pt/SF (silica fiber), Pt/C catalysts modified with cinchonidine under ultrasonic irradiation. The initial rate, regioselectivity and enantioselectivity were investigated for different catalyst pretreatments, solvents and ultrasonic powers. The ultrasound...
Hiroyuki Arikawa et al.
Dental materials journal, 28(4), 454-460 (2009-09-02)
The purpose of this study was to investigate effects of various visible light photoinitiators on the polymerization efficiency and color of the light-activated resins. Four photoinitiators, including camphorquinone, phenylpropanedione, monoacrylphosphine oxide (TPO), and bisacrylphosphine oxide (Ir819), were used. Each photoinitiator...
Walter F Schroeder et al.
Dental materials : official publication of the Academy of Dental Materials, 24(5), 686-693 (2007-09-07)
The present study was carried out in order to assess the suitability of N,N-dimethylaminobenzyl alcohol (DMOH) as co-initiator of camphorquinone (CQ) and 1-phenyl-1,2-propanedione (PPD) in light-cured dental resins. DMOH was synthesized and used as co-initiator for the photopolymerization of a...
Susy Lopes et al.
The journal of physical chemistry. A, 109(25), 5560-5570 (2006-07-13)
1-Phenyl-1,2-propanedione has been isolated in low-temperature xenon matrixes and studied by FTIR spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In good agreement with previous electron diffraction data [Shen, Q.; Hagen, K. J. Phys. Chem. 1993, 97, 985], the calculations predicted the existence...
Terje Christensen et al.
Journal of photochemistry and photobiology. B, Biology, 100(3), 128-134 (2010-06-26)
Documentation is scarce on the photobiological effects of photoinitiators present in dental light curable materials. The aim of this study was to determine cellular effects of the photoinitiators camphorquinone (CQ) and phenyl propanedione (PPD) and to investigate whether these substances...
Y J Park et al.
Dental materials : official publication of the Academy of Dental Materials, 15(2), 120-127 (1999-11-07)
The purpose of this study is to explore the synergistic effect of combining camphorquinone (CQ) with 1-phenyl-1,2-propanedione (PPD) as a new photoinitiator. A BisGMA, UDMA, TEGDMA monomer mixture was made light-curing with CQ and/or PPD plus 0.2 wt.% N,N-cyanoethyl-methylaniline (CEMA)....
Claudia Urbina et al.
Molecules (Basel, Switzerland), 15(5), 3428-3440 (2010-07-27)
The enantioselective hydrogenation of 1-phenyl-1,2-propanedione over Pt colloids stabilized with (R,S)-4,5-dihydro-4,5-diphenyl-2-(6-cyanopyridinyl)imidazoline (CI) supported on a meso-structured ZrO(2) under a pressure of 40 bar of H(2) at 298 K has been investigated(.) The metal loading in all catalysts was 1 wt%....
J-P Mikkola et al.
Ultrasonics sonochemistry, 11(3-4), 233-239 (2004-04-15)
The effect of power ultrasound has been studied in the hydrogenation of 1-phenyl-1,2-propanedione (enantioselective hydrogenation) and linoleic acid (fat hardening). Furthermore the hydrogenation of d-xylose to xylitol and citral to citronellal and citronellol were studied under the influence of acoustic...
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