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Lange T, Leyh B, Dittmer A, Dittmer J. Subtypen-abhängige Reaktionen von Mammakarzinomzelllinien auf Karzinom-assoziierte Fibroblasten. Geburtshilfe Frauenheilkd 2016. [DOI: 10.1055/s-0036-1583554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Leyh B, Dittmer A, Lange T, Dittmer J. Bcl-3 (B-cell leukemia/lymphoma 3) vermittelt die durch stromale Zellen induzierte Desensibilisierung von Brustkrebszellen gegenüber Fulvestrant. Geburtshilfe Frauenheilkd 2016. [DOI: 10.1055/s-0036-1583582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Unverzagt M, Leyh B, Dittmer A, Dittmer J. Inhibitorische Aktivität von Kelch-like 4 auf das Wachstum von Brustkrebszellen. Geburtshilfe Frauenheilkd 2015. [DOI: 10.1055/s-0035-1551636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Leyh B, Dittmer A, Lange T, Dittmer J. Der Einfluss mesenchymaler Stammzellen und Karzinom-assoziierter Fibroblasten auf die Aktivität des PI3K/AKT-Weges und die Anti-Östrogenresistenz in Brustkrebszellen. Geburtshilfe Frauenheilkd 2015. [DOI: 10.1055/s-0035-1551642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Leyh B, Dittmer A, Hellwig V, Dittmer J. Einfluss und Wirkmechanismen mesenchymaler Stammzellen und Carcinom-assoziierter Fibroblasten auf die Genexpression, Migration und Anti-Östrogen-Sensitivität von Mammakarzinomzellen. Geburtshilfe Frauenheilkd 2014. [DOI: 10.1055/s-0034-1376508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Locht R, Dehareng D, Leyh B. Vibronic valence and Rydberg transitions in geminal chloro-fluoro-ethene (1,1-C2H2FCl): a spectroscopic and quantum chemical investigation. Mol Phys 2013. [DOI: 10.1080/00268976.2013.842659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- R. Locht
- Department of Chemistry, Molecular Dynamics Laboratory, University of Liège, Liège, Belgium
| | - D. Dehareng
- Department of Live Sciences, Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - B. Leyh
- Department of Chemistry, Molecular Dynamics Laboratory, University of Liège, Liège, Belgium
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Locht R, Jochims H, Leyh B. The vacuum UV photoabsorption spectroscopy of the geminal ethylene difluoride (1,1-C2H2F2). The vibrational structure and its analysis. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Dittmer J, Dittmer A, Oerlecke I, Leyh B, Martens JWM, Thomssen C. P5-06-08: Mesenchymal Stem Cells and Carcinoma-Associated Fibroblasts Sensitize Breast Cancer Cells in 3D Cultures to Kinase Inhibitors. Cancer Res 2011. [DOI: 10.1158/0008-5472.sabcs11-p5-06-08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Bone-derived mesenchymal stem cells (MSCs) are attracted to cancer lesions and may differentiate to CAFs. By interacting with cancer cells, MSCs and CAFs may promote cancer progression and modulate drug sensitivity.
Material and Methods: To analyze ability of MSCs and CAFs to modulate drug response, we generated spheroids of MCF-7 or MDA-MB-231 breast cancer cells in the absence or presence of human (h) MSCs or hCAFs and tested the susceptibility of the breast cancer cells to three different kinase inhibitors (TKI258, RAD001 and RAF265) as used in cancer therapy.
Results: While MSCs and CAFs did not affect the response of either breast cancer cell line to PDGFR/FGFR/VEGFR inhibitor TKI258, they sensitized breast cancer cells to the mTOR inhibitor RAD001. In MCF-7 cells, this was accompanied by increased apoptosis. hMSCs and to a lesser extent hCAFs also enhanced the cytotoxic effect of RAF inhibitor RAF265 on MDA-MB-231 cells. Searching for the mechanism that underlies the effect of stromal cells on RAF265 response we found that stromal cells inhibited RAF265-induced increase in ERK1/2 phosphorylation, supported RAF265-dependent downregulation of PKCalpha (protein kinase Calpha) and prevented RAF265-induced conversion of LC3B, a marker of autophagy. To mimic the changes in ERK1/2 phosphorylation and PKCalpha expression in response to the stromal cells, we treated cells with MEK1 inhibitor U0126 or PKCalpha inhibitor Gö6976, respectively. U0126, but not Gö6976, was as effective as hMSCs in sensitizing MDA-MB-231 cells to RAF265.
Discussion: Our data suggest that hMSCs and hCAFs increased the cytotoxic effect of RAF265 on MDA-MB-231 cells by downregulating ERK1/2 phosphorylation. In summary, this study shows that hMSCs are able to render breast cancer cells more susceptible to kinase inhibitors and that, to the most part, hCAFs to which hMSCs can differentiate are able to mimic the drug-sensitizing effects of hMSCs.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-06-08.
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Affiliation(s)
- J Dittmer
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
| | - A Dittmer
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
| | - I Oerlecke
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
| | - B Leyh
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
| | - JWM Martens
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
| | - C Thomssen
- 1Clinic for Gynecology University Halle, Germany; Erasmus University Medical Center
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Hoxha A, Yu SY, Locht R, Jochims HW, Leyh B. A photoionization mass spectrometric and threshold photoelectron-photoion coincidence study of vinylbromide (C2H3Br) in the vacuum ultraviolet range of 6–21eV. Chem Phys 2011. [DOI: 10.1016/j.chemphys.2010.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Locht R, Leyh B, Dehareng D, Jochims H, Baumgärtel H. The vacuum UV photoabsorption spectroscopy of vinyl fluoride (C2H3F): The vibrational fine structure and its analysis. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Gridelet E, Locht R, Lorquet AJ, Lorquet JC, Leyh B. The Role of Long-Range Forces in the Determination of Translational Kinetic Energy Release. Loss of C4H4+ from the Benzene and Pyridine Cations. J Phys Chem A 2008; 112:10086-95. [DOI: 10.1021/jp8033424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- E. Gridelet
- Department of Chemistry, University of Liège, Sart-Tilman (B6), B-4000 Liège 1, Belgium
| | - R. Locht
- Department of Chemistry, University of Liège, Sart-Tilman (B6), B-4000 Liège 1, Belgium
| | - A. J. Lorquet
- Department of Chemistry, University of Liège, Sart-Tilman (B6), B-4000 Liège 1, Belgium
| | - J. C. Lorquet
- Department of Chemistry, University of Liège, Sart-Tilman (B6), B-4000 Liège 1, Belgium
| | - B. Leyh
- Department of Chemistry, University of Liège, Sart-Tilman (B6), B-4000 Liège 1, Belgium
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Locht R, Leyh B, Dehareng D, Hottmann K, Jochims H, Baumgärtel H. About the photoionization of methyl bromide (CH3Br). Photoelectron and photoionization mass spectrometric investigation. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.10.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gridelet E, Lorquet AJ, Locht R, Lorquet JC, Leyh B. Hydrogen Atom Loss from the Benzene Cation. Why Is the Kinetic Energy Release so Large? J Phys Chem A 2006; 110:8519-27. [PMID: 16821836 DOI: 10.1021/jp056119h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The kinetic energy release distributions (KERDs) associated with the hydrogen loss from the benzene cation and the deuterium loss from the perdeuteriobenzene cation have been remeasured on the metastable time scale and analyzed by the maximum entropy method. The experimental kinetic energy releases are larger than expected statistically, in contradistinction to what has been observed for the C-X fragmentations of the halogenobenzene cations. H(D) loss from C(6)H(6)(+) (C(6)D(6)(+)) occurs via a conical intersection connecting the (2)A(2) and (2)A(1) electronic states. Two models are proposed to account for the experimental data: (i) a modified orbiting transition state theory (OTST) approach incorporating electronic nonadiabaticity; (ii) an electronically nonadiabatic version of the statistical adiabatic channel model (SACM) of Quack and Troe. The latter approach is found to be preferable. It leads to the conclusion that the larger the energy stored in the transitional modes, which partly convert to the relative interfragment motion, the shorter the value of the reaction coordinate at which the adiabatic channels cross, and the larger the probability of undergoing the (2)A(2) --> (2)A(1) transition required for hydrogen loss.
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Affiliation(s)
- E Gridelet
- Department of Chemistry, Molecular Dynamics Laboratory, University of Liège, B-4000 Sart-Tilman, Belgium
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14
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Locht R, Leyh B, Dehareng D, Jochims H, Baumgärtel H. The vacuum UV photoabsorption spectrum of methyl bromide (CH3Br) and its perdeuterated isotopomer CD3Br: a vibrational analysis. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Locht R, Leyh B, Jochims H, Baumgärtel H. The vacuum UV photoabsorption spectrum of methyl bromide (CH3Br) and its perdeuterated isotopomer CD3Br: a Rydberg series analysis. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Gridelet E, Dehareng D, Locht R, Lorquet AJ, Lorquet JC, Leyh B. Ground and Excited State Dissociation Dynamics of Ionized 1,1-Difluoroethene. J Phys Chem A 2005; 109:8225-35. [PMID: 16834209 DOI: 10.1021/jp051542b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The kinetic energy release distributions (KERDs) for the fluorine atom loss from the 1,1-difluoroethene cation have been recorded with two spectrometers in two different energy ranges. A first experiment uses dissociative photoionization with the He(I) and Ne(I) resonance lines, providing the ions with a broad internal energy range, up to 7 eV above the dissociation threshold. The second experiment samples the metastable range, and the average ion internal energy is limited to about 0.2 eV above the threshold. In both energy domains, KERDs are found to be bimodal. Each component has been analyzed by the maximum entropy method. The narrow, low kinetic energy components display for both experiments the characteristics of a statistical, simple bond cleavage reaction: constraint equal to the square root of the fragment kinetic energy and ergodicity index higher than 90%. Furthermore, this component is satisfactorily accounted for in the metastable time scale by the orbiting transition state theory. Potential energy surfaces corresponding to the five lowest electronic states of the dissociating 1,1-C2H2F2+ ion have been investigated by ab initio calculations at various levels. The equilibrium geometry of these states, their dissociation energies, and their vibrational wavenumbers have been calculated, and a few conical intersections between these surfaces have been identified. It comes out that the ionic ground state X2B1 is adiabatically correlated with the lowest dissociation asymptote. Its potential energy curve increases in a monotonic way along the reaction coordinate, giving rise to the narrow KERD component. Two states embedded in the third photoelectron band (B2A1 at 15.95 eV and C2B2 at 16.17 eV) also correlate with the lowest asymptote at 14.24 eV. We suggest that their repulsive behavior along the reaction coordinate be responsible for the KERD high kinetic energy contribution.
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Affiliation(s)
- E Gridelet
- Department of Chemistry, Molecular Dynamics Laboratory, Building B6c, and Centre for Protein Engineering, Building B6a, University of Liège, B-4000 SART-TILMAN, Belgium
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17
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Vangeyte P, Leyh B, De Clercq C, Auvray L, Misselyn-Bauduin AM, Jérôme R. Concomitant adsorption of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers and sodium dodecyl sulfate at the silica-water interface. Langmuir 2005; 21:7710-6. [PMID: 16089373 DOI: 10.1021/la047051k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Upon addition of silica to aqueous solutions of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers (PEO-b-PCL) and sodium dodecyl sulfate (SDS), adsorption of the solutes occurs at the silica-water interface. The amount of the adsorbed constituents has been measured by the total concentration depletion method. Small-angle neutron scattering experiments (SANS) have been carried out to investigate the structure of the adsorbed layer. Although SDS is not spontaneously adsorbed onto hydrophilic silica, adsorption is observed in the presence of PEO-b-PCL diblocks, in relation to the relative concentration of the two compounds. Conversely, SDS has a depressive effect on the adsorption of the copolymer, whose structure at the interface is modified. Copolymer desorption is however never complete at high SDS content. These observations have been rationalized by the associative behavior of PEO-b-PCL and SDS in water.
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Affiliation(s)
- P Vangeyte
- Center for Education and Research on Macromolecules, University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
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Vangeyte P, Leyh B, Rojas OJ, Claesson PM, Heinrich M, Auvray L, Willet N, Jérôme R. Adsorption of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers at the silica-water interface. Langmuir 2005; 21:2930-2940. [PMID: 15779968 DOI: 10.1021/la047425+] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The adsorption of amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) and poly(ethylene oxide)-b-poly(gamma-methyl-epsilon-caprolactone) copolymers in aqueous solution on silica and glass surfaces has been investigated by flow microcalorimetry, small-angle neutron scattering (SANS), surface forces, and complementary techniques. The studied copolymers consist of a poly(ethylene oxide) (PEO) block of M(n) = 5000 and a hydrophobic polyester block of poly(epsilon-caprolactone) (PCL) or poly(gamma-methyl-epsilon-caprolactone) (PMCL) of M(n) in the 950-2200 range. Compared to homoPEO, the adsorption of the copolymers is significantly increased by the connection of PEO to an aliphatic polyester block. According to calorimetric experiments, the copolymers interact with the surface mainly through the hydrophilic block. At low surface coverage, the PEO block interacts with the surface such that both PEO and PCL chains are exposed to the aqueous solution. At high surface coverage, a dense copolymer layer is observed with the PEO blocks oriented toward the solution. The structure of the copolymer layer has been analyzed by neutron scattering using the contrast matching technique and by tapping mode atomic force microscopy. The experimental observations agree with the coadsorption of micelles and free copolymer chains at the interface.
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Affiliation(s)
- P Vangeyte
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
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Gridelet E, Lorquet JC, Leyh B. Role of angular momentum conservation in unimolecular translational energy release: Validity of the orbiting transition state theory. J Chem Phys 2005; 122:094106. [PMID: 15836111 DOI: 10.1063/1.1856917] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The translational kinetic energy release distribution (KERD) for the halogen loss reaction of the bromobenzene and iodobenzene cations has been reinvestigated on the microsecond time scale. Two necessary conditions of validity of the orbiting transition state theory (OTST) for the calculation of kinetic energy release distributions (KERDs) have been formulated. One of them examines the central ion-induced dipole potential approximation. As a second criterion, an adiabatic parameter is derived. The lower the released translational energy and the total angular momentum, the larger the reduced mass, the rotational constant of the molecular fragment, and the polarizability of the released atom, the more valid is the OTST. Only the low-energy dissociation of the iodobenzene ion (E approximately 0.45 eV, where E is the internal energy above the reaction threshold) is found to fulfill the criteria of validity of the OTST. The constraints that act on the dissociation dynamics have been studied by the maximum entropy method. Calculations of entropy deficiencies (which measure the deviation from a microcanonical distribution) show that the pair of fragments does not sample the whole of the phase space that is compatible with the mere specification of the internal energy. The major constraint that results from conservation of angular momentum is related to a reduction of the dimensionality of the dynamics of the translational motion to a two-dimensional space. A second and minor constraint that affects the KERD leads to a suppression of small translational releases, i.e., accounts for threshold behavior. At high internal energies, the effects of curvature of the reaction path and of angular momentum conservation are intricately intermeddled and it is not possible to specify the share of each effect.
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Affiliation(s)
- E Gridelet
- Department of Chemistry, Molecular Dynamics Laboratory, Building B6c, University of Liège, B-4000 Sart-Tilman, Belgium
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Vangeyte P, Leyh B, Auvray L, Grandjean J, Misselyn-Bauduin AM, Jérôme R. Mixed self-assembly of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers and sodium dodecyl sulfate in aqueous solution. Langmuir 2004; 20:9019-9028. [PMID: 15461482 DOI: 10.1021/la048848e] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Interaction of amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers with anionic sodium dodecyl sulfate (SDS) has been investigated in aqueous solution. Formation of mixed micelles has been confirmed by surface tension measurements, whereas the influence of the surfactant on the copolymer self-assembling has been studied by measurement of the 1H NMR self-diffusion coefficients and by small-angle neutron scattering. As a rule, the surfactant decreases the heterogeneity of the micellar structures formed by the copolymer in water. Moreover, increasing the content of SDS results in the increasingly more important extension of the poly(ethylene oxide) (PEO) corona chains and the copolymer micelle deaggregation. The stability of the micelles against SDS increases with the length of the hydrophobic block. Preliminary two-dimensional NMR measurements with nuclear Overhauser enhancement have confirmed the spatial vicinity between SDS and the constitutive blocks of the copolymer.
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Affiliation(s)
- P Vangeyte
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
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Vangeyte P, Leyh B, Heinrich M, Grandjean J, Bourgaux C, Jérôme R. Self-assembly of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers in aqueous solution. Langmuir 2004; 20:8442-8451. [PMID: 15379459 DOI: 10.1021/la049695y] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The associative behavior of monodisperse diblock copolymers consisting of a hydrophilic poly(ethylene oxide) block and a hydrophobic poly(epsilon-caprolactone) or poly(gamma-methyl-epsilon-caprolactone) block has been studied in aqueous solution. Copolymers have been directly dissolved in water. The solution properties have been studied by surface tension, in relation to mesoscopic analyses by NMR (self-diffusion coefficients), transmission electron microscopy, and small-angle neutron and X-ray scattering. The experimental results suggest that micellization occurs at low concentration (approximately 0.002 wt %) and results in a mixture of unimers and spherical micelles that exchange slowly. The radius of the micelles has been measured (ca. 11 nm), and the micellar substructure has been extracted from the fitting of the SANS data with two analytical models. The core radius and the aggregation number change with the hydrophobic block length according to scaling laws as reported in the scientific literature. The poly(ethylene oxide) blocks are in a moderately extended conformation in the corona, which corresponds to about 25% of the completely extended chain. No significant modification is observed when poly(gamma-methyl-epsilon-caprolactone) replaces poly(epsilon-caprolactone) in the diblocks.
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Affiliation(s)
- P Vangeyte
- Center for Education and Research on Macromolecules, Laboratoire de Dynamique Moleculaire, University of Liège, Sart-Tilman B6a, B-4000, Belgium
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Fati D, Lorquet AJ, Locht R, Lorquet JC, Leyh B. Kinetic Energy Release Distributions for Tropylium and Benzylium Ion Formation from the Toluene Cation. J Phys Chem A 2004. [DOI: 10.1021/jp048058d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- D. Fati
- Department of Chemistry, University of Liège, Sart-Tilman, Building B6c, B-4000 Liège 1, Belgium
| | - A. J. Lorquet
- Department of Chemistry, University of Liège, Sart-Tilman, Building B6c, B-4000 Liège 1, Belgium
| | - R. Locht
- Department of Chemistry, University of Liège, Sart-Tilman, Building B6c, B-4000 Liège 1, Belgium
| | - J. C. Lorquet
- Department of Chemistry, University of Liège, Sart-Tilman, Building B6c, B-4000 Liège 1, Belgium
| | - B. Leyh
- Department of Chemistry, University of Liège, Sart-Tilman, Building B6c, B-4000 Liège 1, Belgium
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Locht R, Leyh B, Hoxha A, Jochims H, Baumgärtel H. The vacuum UV photoabsorption spectrum of methyl chloride (CH3Cl) and its perdeuterated isotopomer CD3Cl I. A Rydberg series analysis. Chem Phys 2001. [DOI: 10.1016/s0301-0104(01)00464-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Locht R, Leyh B, Hoxha A, Dehareng D, Jochims H, Baumgärtel H. The vacuum UV photoabsorption spectrum of methyl chloride (CH3Cl) and its perdeuterated isotopomer CD3Cl. Chem Phys 2001. [DOI: 10.1016/s0301-0104(01)00465-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Hoxha A, Collette C, De Pauw E, Leyh B. Mechanism of Collisional Heating in Electrospray Mass Spectrometry: Ion Trajectory Calculations. J Phys Chem A 2001. [DOI: 10.1021/jp002575o] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Hoxha
- Laboratoire de Dynamique Moléculaire and Laboratoire de Spectrométrie de Masse, Département de Chimie, B6c, Université de Liège, Sart-Tilman, B-4000 Liège 1, Belgium
| | - C. Collette
- Laboratoire de Dynamique Moléculaire and Laboratoire de Spectrométrie de Masse, Département de Chimie, B6c, Université de Liège, Sart-Tilman, B-4000 Liège 1, Belgium
| | - E. De Pauw
- Laboratoire de Dynamique Moléculaire and Laboratoire de Spectrométrie de Masse, Département de Chimie, B6c, Université de Liège, Sart-Tilman, B-4000 Liège 1, Belgium
| | - B. Leyh
- Laboratoire de Dynamique Moléculaire and Laboratoire de Spectrométrie de Masse, Département de Chimie, B6c, Université de Liège, Sart-Tilman, B-4000 Liège 1, Belgium
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Locht R, Leyh B, Hoxha A, Dehareng D, Jochims H, Baumgärtel H. About the vacuum UV photoabsorption spectrum of methyl fluoride (CH3F): the fine structure and its vibrational analysis. Chem Phys 2000. [DOI: 10.1016/s0301-0104(00)00167-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hoxha A, Locht R, Lorquet AJ, Lorquet JC, Leyh B. Unimolecular dynamics from kinetic energy release distributions. V. How does the efficiency of phase space sampling vary with internal energy? J Chem Phys 1999. [DOI: 10.1063/1.479840] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Urbain P, Leyh B, Remacle F, Lorquet AJ, Flammang R, Lorquet JC. Unimolecular reaction dynamics from kinetic energy release distributions. III. A comparative study of the halogenobenzene cations. J Chem Phys 1999. [DOI: 10.1063/1.477934] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Locht R, Leyh B, Hottmann K, Baumgärtel H. The He(I), threshold photoelectron and constant ion state spectroscopy of vinylchloride (C2H3Cl). Chem Phys 1997. [DOI: 10.1016/s0301-0104(97)00128-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Urbain P, Remacle F, Leyh B, Lorquet JC. Unimolecular Reaction Dynamics from Kinetic Energy Release Distributions. 2. A Study of the Reaction C6H5Br+ → C6H5+ + Br by the Maximum Entropy Method. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp953069f] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- P. Urbain
- Département de Chimie, Sart Tilman, B6, Université de Liège, B4000 Liège 1, Belgium
| | - F. Remacle
- Département de Chimie, Sart Tilman, B6, Université de Liège, B4000 Liège 1, Belgium
| | - B. Leyh
- Département de Chimie, Sart Tilman, B6, Université de Liège, B4000 Liège 1, Belgium
| | - J. C. Lorquet
- Département de Chimie, Sart Tilman, B6, Université de Liège, B4000 Liège 1, Belgium
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Leyh B, Hautot D. Mechanisms of single-electron capture by the dichlorocarbene dication. J Am Soc Mass Spectrom 1996; 7:266-275. [PMID: 24203298 DOI: 10.1016/1044-0305(95)00652-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/1995] [Revised: 10/03/1995] [Accepted: 10/03/1995] [Indexed: 06/02/2023]
Abstract
The single-electron capture (SEC) by dichlorocarbene dications with eight different atomic and molecular target gases, CCl 2 (2+) + G → CCl 2 (+) + G(+), has been studied by product ion spectroscopy and ion kinetic energy spectroscopy. The experimental data have been interpreted in the framework of a theoretical model mat describes the charge exchange process. Exothermic charge exchange is handled within the Landau-Zener model, whereas endothermic charge exchange is described by the Demkov model. The calculated data reproduce qualitatively the essential features of the experimental results: (1) the appearance of a reaction window centered at an exothermicity in the 4-4.5-eV range, (2) the lower SEC cross sections for endothermic charge exchange, (3) the wider internal energy distributions obtained for CCl 2 (+) in the endothermic regime than in the exothermic one, which results in larger dissociation yields, (4) the excitation of molecular targets that accompany their ionization in the SEC process, and (5) the kinetic energy released on the CCl(+) + Cl fragments in dissociative SEC.
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Affiliation(s)
- B Leyh
- Departement de Chimie Générale et de Chimie Physique, Bâtiment B6c, Université de Liège, B. 4000 Sart-Tilman, Liège 1, Belgium
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Leyh B, Hautot D. Reactivity of collisionally activated dichlorocarbene dications studied by tandem mass spectrometry. J Am Soc Mass Spectrom 1995; 6:1019-1029. [PMID: 24214048 DOI: 10.1016/1044-0305(95)00471-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/1995] [Revised: 05/09/1995] [Accepted: 05/09/1995] [Indexed: 06/02/2023]
Abstract
The dissociation mechanisms of dichlorocarbene dications following collisional activation have been investigated via tandem mass spectrometric techniques and semi-empirical calculations. Three channels appear to be significant: {fx1019-1} The second channel becomes dominant at high internal energy. Production of ground state fragments (channel 1) involves a transition driven by spin-orbit coupling from the CCl 2 (2+) [Formula: see text] state to the CCl 2 (2-) ā(3)Σ u (-) state en route to the fragments. The dissociation barrier for the production of ground state fragments from the ground electronic state of CCl 2 (2+) via the spin-orbit-induced transition is equal to 420 kJ mol(-1). The dissociation pathway that corresponds to channel 3 includes a first isomerization step from the linear Cl-C-Cl(2+) structure to a bent Cl-Cl-C(2+) connectivity. The calculated isomerization barrier amounts to 550 kJ mol(-1). The calculated reverse activation barriers are compatible with the measured kinetic energy released on the fragments.
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Affiliation(s)
- B Leyh
- Département de Chimie Générale et de Chimie Physique, Institut de Chimie, Bātiment B6, Université de Liège, Liège 1, B. 4000, Sart-Tilman, Belgium
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Lorquet JC, Leyh B. Unimolecular reaction dynamics from kinetic energy release distributions. 1—dissociation of bromobenzene ions. ACTA ACUST UNITED AC 1993. [DOI: 10.1002/oms.1210281038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Leyh B, Raseev G. Theoretical study of electronic autoionization in CO: Vibrationally resolved results between 17 and 18.3 eV. Phys Rev A Gen Phys 1986; 34:2920-2935. [PMID: 9897610 DOI: 10.1103/physreva.34.2920] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Dehareng D, Leyh B, Desouter‐Lecomte M, Lorquet JC, Delwiche J, Hubin‐Franskin MJ. Intramolecular dynamics by photoelectron spectroscopy. II. Nonadiabatic processes. J Chem Phys 1983. [DOI: 10.1063/1.446292] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Lineweaver-Burk, Hanes, Eadie-Hofstee and Dixon plots can only be used when a true initial rate is measured. Despite the fact that this point has often been stressed, it is far too often ignored in favour of restricting the assay time to one where low amounts of substrate are used. When one or several irreversible and slow steps occur with an inactivator during the incubation of a ternary enzyme-substrate-inactivator mixture, the rate of the enzyme-catalysed reaction progressively decreases. Even under these conditions, the present computer simulations investigations show that apparently linear Lineweaver-Burk, Hanes, Eadie-Hofstee and Dixon graphs can be obtained when the amount of product formed is mistakenly assumed to represent the true initial rate. Moreover, the observed pattern can change with time, going for instance from non-competitive to competitive. "Ki's" measured under these conditions also vary with time and bear little relationship to the true constants involved in the interaction.
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