The reaction system CH3+OH at intermediate temperatures. Appearance of a new product channel

Humpfer, R.; Oser, Harald; Grotheer, Horst-Henning; Just, Th.

doi:10.1016/s0082-0784(06)80704-6

Cited by 18 publications

(23 citation statements)

References 23 publications

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“…The recombination rate constants for CH 3 + OH → CH 3 OH, at high‐pressure limit, were finally determined as the ratio between dissociation rate constants and equilibrium constants. Figure 6 shows a comparison of our calculated rate constants (obtained from MRPT(6,4)/ACCD//CAS(6,4)/ACCD data and related dissociation rate constants and equilibrium constants) and literature data 57–63. These recombination rate constants (in cm 3 molecule −1 s −1 ) are best fitted to: The best agreement of our predicted rate constants and the literature values have been found for our MRPT(6,4)/ACCD//CAS(6,4)/ACCD data, being these rate constants and Arrhenius parameters suggested for methanol dissociation and radicals recombination reactions.…”

Section: Resultssupporting

confidence: 66%

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Blaise

Mahjoub

Salvat

et al. 2009

Arthritis & Rheumatism

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Objective. To demonstrate the activation of the Notch signaling pathway during changes in the phenotype of chondrocytes in vitro, and to assess the influence of Notch on the production of chondrocyte markers.Methods. Serial monolayer primary cultures of murine articular chondrocytes (MACs), as a model of chondrocyte dedifferentiation, were prepared. MACs were cultured with or without a Notch inhibitor and transfected with different Notch-expressing vectors. The Notch pathway and chondrocyte marker profiles were assessed by quantitative reverse transcriptionpolymerase chain reaction, immunoblotting, and immunocytochemistry.Results. Successive passages of MACs resulted in a loss of type II collagen and aggrecan (chondrocyte differentiation markers), an increase in type I collagen (dedifferentiation marker), an increase in Notch ligands, and augmented target gene activity. The Notch inhibitor decreased the type II collagen protein content but had no effect on Col2a1 messenger RNA, while transfection with the constitutive active forms of the Notch1 receptor led to a decrease in type II collagen in transfected cells. In assays to investigate the mechanism of type II collagen breakdown, matrix metalloproteinase 13 (MMP-13) synthesis was regulated in a Notchdependent manner, whereas MMP-2 synthesis was unchanged.Conclusion. The Notch signaling pathway is associated with decreased type II collagen production during the dedifferentiation of MACs in vitro. This may be correlated with the increase in MMP-13 production linked to activation of Notch.

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Section: Resultssupporting

confidence: 66%

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Blaise

Mahjoub

Salvat

et al. 2009

Arthritis & Rheumatism

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“…Humpfer et al (1994) assume the CH 30H product channel to be dominating with a rate constant at 1000K of 9·\013 cm 3/mol/s. However, recent experimental (Deters et al, 1998) and theoretical studies (Pereira et al, 1997) suggest a ten fold lower rate for (54) and favour production of CH 2(s) and H 20 through (51 …”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Low temperature oxidation of methane: the influence of nitrogen oxides

Bendtsen

Glarborg

Dam‐Johansen

2000

Combustion Science and Technology

104

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An experimental investigation of methane oxidation in the presence of NO and N0 2 has been made in an isothermal plug-flow reactor at 750-1250K. The temperature for on-set of oxidation was lowered by 250 K in the presence of NO or NO z at residence times of 200 ms. At shorter residence times (140 ms) this enhancement effect is reduced for NO but maintained for N0 2 . Furthermore two temperature regimes of oxidation separated by an intermediate regime where only little oxidation takes place exist at residence times of 140 ms, if NO is the only nitrogen oxide initially present. The results were explained by the competition between three reaction paths from CH 3 to CHzO. A direct high temperature path (A), a two-step N0 2 enhanced low temperature path (B) and a slow three step NO enhanced path (C), which may produce N0 2 to activate path B. The negative temperature coefficient behaviour was explained by a competition between paths (A) and (C). A previously published reaction set was modified to take these reaction patterns into account.The processes discussed here presumably occur to some extent in the exhaust of natural gas engines, but conditions may be modified, either to ensure an enhanced activity to oxidize methane in the exhaust, or alternatively to decrease the activity to reduce the production of unwanted intennediates such as fonnaldehyde.

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“…1 CH 2 +H 2 O, 3 CH 2 +H 2 O, CH 2 O+H 2 , HCOH+H 2 , and CH 2 OH+H 101,102. The overall rate constant is fairly well established, but in the low‐pressure and falloff region, branching ratios are uncertain and reported values deviate significantly 101, 103–105. The preferred rate constant for the stabilization channel k 8 is taken from the study by De Avillez Pereira et al 101 with He as bath gas.…”

Section: Detailed Kinetic Modelmentioning

confidence: 99%

Experimental measurements and kinetic modeling of CH₄/O₂ and CH₄/C₂H₆/O₂ conversion at high pressure

Rasmussen

Jakobsen

Glarborg

2008

Int J of Chemical Kinetics

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A detailed chemical kinetic model for homogeneous combustion of the light hydrocarbon fuels CH4 and C2H6 in the intermediate temperature range roughly 500–1100 K, and pressures up to 100 bar has been developed and validated experimentally. Rate constants have been obtained from critical evaluation of data for individual elementary reactions reported in the literature with particular emphasis on the conditions relevant to the present work. The experiments, involving CH4/O2 and CH4/C2H6/O2 mixtures diluted in N2, have been carried out in a high‐pressure flow reactor at 600–900 K, 50–100 bar, and reaction stoichiometries ranging from very lean to fuel‐rich conditions. Model predictions are generally satisfactory. The governing reaction mechanisms are outlined based on calculations with the kinetic model. Finally, the mechanism was extended with a number of reactions important at high temperature and tested against data from shock tubes, laminar flames, and flow reactors. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 778–807, 2008

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The reaction system CH3+OH at intermediate temperatures. Appearance of a new product channel

Cited by 18 publications

References 23 publications

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Low temperature oxidation of methane: the influence of nitrogen oxides

Experimental measurements and kinetic modeling of CH₄/O₂ and CH₄/C₂H₆/O₂ conversion at high pressure

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The reaction system CH3+OH at intermediate temperatures. Appearance of a new product channel

Cited by 18 publications

References 23 publications

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Involvement of the notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage

Low temperature oxidation of methane: the influence of nitrogen oxides

Experimental measurements and kinetic modeling of CH4/O2 and CH4/C2H6/O2 conversion at high pressure

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Experimental measurements and kinetic modeling of CH₄/O₂ and CH₄/C₂H₆/O₂ conversion at high pressure