STUDENTS’ LOYALTY: DOES VALUE CO-CREATION IN HIGHER EDUCATION INSTITUTIONS MATTER?

This study investigates the influence for intrinsic and extrinsic motives on customers` participation in value co-creation activities (CPVCA), beside examining the direct and indirect impact for CPVCA on customers` loyalty. Quantitative research approach is used, while the study population encompasses all Lebanese private universities students. A questionnaire was developed to gather data from 403 universities` students who were chosen using the convenience sampling technique. PLS-SEM was adopted to examine the study proposed scale validity and the relationships between its latent variables. The current study results indicate a positive influence for both intrinsic and extrinsic motives on CPVCA. Also, the findings reveal a significant direct relationship among CPVCA and customer loyalty, as well as an indirect relationship via mediating brand experience

Extracorporeal shock waves down-regulate the expression of interleukin-10 and tumor necrosis factor-alpha in osteoarthritic chondrocytes

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to investigate the effects of extra corporeal shock waves (ESW) therapy on the metabolism of healthy and osteoarthritic human chondrocytes, and particularly on the expression of IL-10, TNF-alpha and beta1 integrin.</p> <p>Methods</p> <p>Human adult articular cartilage was obtained from 9 patients (6 male and 3 females), with primary knee osteoarthritis (OA), undergoing total joint replacement and from 3 young healthy donors (HD) (2 males, 1 female) with joint traumatic fracture. After isolation, chondrocytes underwent ESW treatment (electromagnetic generator system, MINILITH SL1, STORZ MEDICAL) at different parameters of impulses, energy levels and energy flux density. After that, chondrocytes were cultured in 24-well plate in DMEM supplemented with 10% FCS for 48 hours and then beta₁integrin surface expression and intracellular IL-10 and TNF-alpha levels were evaluated by flow-cytometry.</p> <p>Results</p> <p>At baseline, osteoarthritic chondrocytes expressed significantly lower levels of beta1 integrin and higher levels and IL-10 and TNF-alpha levels. Following ESW application, while beta1 integrin expression remain unchanged, a significant decrease of IL-10 and TNF-alpha intracellular levels was observed both in osteoarthritic and healthy chondrocytes. IL-10 levels decreased at any impulses and energy levels, while a significant reduction of TNF-alpha was mainly found at middle energies.</p> <p>Conclusion</p> <p>Our study confirmed that osteoarthritic chondrocytes express low beta₁integrin and high TNF-alpha and IL-10 levels. Nonetheless, ESW treatment application down-regulate the intracellular levels of TNF-alpha and IL-10 by chondrocytes, suggesting that ESW might restore TNF-alpha and IL-10 production by osteoarthritic chondrocytes at normal levels. However, further in vivo and in vitro studies are necessary to establish if ESW can represent a viable option in the treatment of OA.</p

Complexes Organométalliques des Groupes 3 et 13 : Applications en Chimie Fine et Catalyse de Polymérisation

Thèse de Doctorat de l'Université de Rennes

An efficient method to synthesize vinyl ethers (VEs) that bear various halogenated or functional groups and their radical copolymerization with chlorotrifluoroethylene (CTFE) to yield functional poly(VE-alt-CTFE) alternated copolymers

International audienceAn air-stable palladium catalyst formed in situ from commercially available components efficiently catalyzed the transetherification between ethyl vinyl ether and various alcohols to lead to the corresponding original vinyl ethers in 40-84% yield in a single step. First, a series of vinyl ether monomers that bear various functional groups, such as halogenomethyl groups, amino groups, carbonate side-groups, oligo(ethylene oxide), and oligo(fluoroether) chains, were prepared and characterized by 1H and 13C NMR spectroscopy. Then, radical copolymerization of such novel vinyl ethers with chlorotrifluoroethylene (CTFE) led to alternating poly(CTFE-alt-VE) copolymers that contained various functional dangling groups. A series of copolymers with different amounts of functional groups were obtained in fair to good yield (32-81%). Their alternating structure was confirmed by elemental analysis as well as by 1H, 19F, and 13C NMR spectroscopy. Their thermogravimetric analyses under airshowed decomposition temperatures at 10% weight loss (Td,10%) ranging from 214 to 324 C. The oligo(fluoroether) chain-based copolymers appeared more thermostable than those based on other various functional groups

Radical Telomerization of Fluorinated Alkenes with Dialkyl Hydrogenophosphonates

International audienceThis review summarizes various surveys on the synthesis of fluoroalkyl phosphonate derivatives by radical telomerization of fluorinated olefins with dialkyl H-phosphonates. For the past fifty years, numerous authors have reported such reactions involving a wide range of fluorinated olefins. Each class of fluorinated olefins is discussed in a dedicated paragraph, along with the influence that different parameters may have on the telomerization reactions: the nature of the solvent, the initial molar ratio of the reactants, the effect of the alkyl chain length of the H-phosphonates, and the nature of the initiator. Special attention has been given to the reported NMR data related to the adducts resulting from such reactions. The work discussed here opens up opportunities for further investigations that could deepen the knowledge on fluorinated derivatives of phosphonic acid

Synthesis and Characterization of Original Alternated Fluorinated Copolymers Bearing Glycidyl Carbonate Side Groups

International audienceA vinyl ether bearing a carbonate side group (2- oxo-1,3-dioxolan-4-yl-methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert-butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE-alt-F-alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as 1H, 19F, and 13C NMR spectroscopy. All copolymers were obtained in good yield (73-85%), with molecular weights ranging from 3900 to 4600 g mol 1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (Td,10%) in the 284-330 C range. The HFP-based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15-65 C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries

Recent Advances on New Fluorinated Copolymers Based on Carbonate and Oligo(ethylene oxide) by Radical Copolymerization

The synthesis and characterizations of original poly[CTFEalt-VEoligo(EO)] and poly(F-alkene-alt-GCVE) alternated copolymers (where CTFE, VEoligo(EO), and F-alkene stand for chlorotrifluoroethylene, oligo(ethylene oxide) vinyl ether, hexafluoropropylene (HFP) or perfluoromethyl vinyl ether (PMVE), and glycerol carbonate vinyl ether, respectively) are presented. First, vinyl ethers bearing oligo(ethylene oxide) or carbonate side-group (i.e. 2-oxo-1,3-dioxolan-4-yl-methyl vinyl ether, GCVE) were synthesized by transetherification of ω-hydroxyl oligo(EO) (of different molecular weights (3 and 10 EO units) or glycerol carbonate with ethyl vinyl ether catalyzed by a palladium complex were obtained in 45-74% yields. Although HFP, PMVE, and vinyl ethers do not homopolymerize under radical conditions, they copolymerized readily yielding alternated poly(F-alkene-alt-VE) copolymers that bore carbonate group or oligo(EO) side-chains. The alternated structures of these original poly(F-alkenes-alt-VE) copolymers were confirmed by elemental analysis and by 1H, 19F and 13C NMR spectroscopy. All copolymers were obtained in good yield (61-85 %). Their molecular weights varied depending on the [initiator]o/[monomers]o intial molar ratios, reaching either 3,900-4,600 g mol-1 or 19,000 g.mol-1 with polydispersities below 2.0

Novel Method to Assess the Molecular Weights of Fluoropolymers by Radical Copolymerization of Vinylidene Fluoride with Various Fluorinated Comonomers Initiated by a Persistent Radical

International audienceBatch radical homopolymerization of vinylidene fluoride (VDF) and its copolymerizations with seven fluorinated comonomers such as H2CCRACF3 (where RA stands for H, F, CO2R (R = H or tBu) or F2CCFRB (RB: H, CF3, OCF3) initiated by *CF3 radical generated from a perfluoro-3-ethyl-2,4-dimethyl-3-pentyl persistent radical (PPFR) are presented. That highly perfluorinated branched radical itself was unable to directly initiate the copolymerization in contrast to the generated trifluoromethyl radical that was successful. The microstructures of the resulting PVDFs, poly(VDF-co-H2CCRACF3) or poly(VDF-co-F2CCFRB) (co)polymers were assessed by 19F and 1H NMR spectroscopy. 19F NMR spectra displayed a quintet centered at −61 ppm assigned to a CF3 end-group which enabled one to determine both the molecular weights of the resulting (co)polymers and the amounts (numbers and molar percentages) of these above comonomers. In all cases, the regioselective radical addition of *CF3 onto the methylene site of VDF was noted as well as for 3,3,3-trifluoropropene. In addition, the 19F NMR spectra showed the absence of signals attributed to PPFR or its derivatives. According to [PPFR]o/([VDF]o + [comonomers]o) initial molar ratios, this novel initiating system could produce high molecular weight-fluoropolymers (up to 200 000 g*mol−1). The lower that ratio, the higher their molecular weights as well as the higher their thermal stability (a 10% weight loss under air was noted at 425 °C). Although the kinetics of radical copolymerization were not studied, the presence of branched persistent radical did not disturb the reactivities of the comonomers and it was not involved in the primary recombination of radicals in the termination step of the polymerization while the macromolecular recombination was favored. For an initial PPFR concentration lower than 1 mol %, a feed ratio of ca. 20 mol % of 2-trifluoromethacrylic acid, MAF (or tert-butyl 2-trifluoromethacrylate, MAF−TBE) led to alternated poly(VDF-alt-MAF or MAF−TBE) copolymers. High yields (90%) of copolymers based on VDF and 2,3,3,3-tetrafluoroprop-1-ene, hexafluoropropylene (HFP), or perfluoromethyl vinyl ether (PMVE) comonomers were achieved while those from MAF, MAF−TBE, trifluoroethylene, and 3,3,3-trifluoropropene were fair to satisfactory. As expected, for a reasonable amount of HFP and PMVE inserted in the copolymers (>18 mol %), elastomers endowed with low Tg values (−35 and −42 °C, respectively) were produced. In addition, the higher the content of VDF, the lower the Tg, though the presence of tBu from MAF−TBE slightly increased the Tg values. Copolymers containing MAF or MAF−TBE exhibited poor thermostability (that arises from the decarboxylation and isobutylene elimination from MAF or MAF−TBE, respectively) in contrast to the other VDF-containing copolymers that showed decomposition from 250 °C under air