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Causas que incidieron en la desaceleracion del crecimiento en la industria en el Libano Tolima

Este trabajo precisa algunas de las causas que incidieron en la desaceleración del crecimiento en la Industria en el Líbano Tolima. La investigación es documental enmarcada dentro del tipo descriptivo, exploratorio, correlacional o explicativo. Se tuvo en cuenta la población mayor a 70 años, se entrevistaron a 35 personas que dieron información a cerca del proceso de la industria a través de las diferentes etapas enmarcadas en la investigación. Los instrumentos utilizados fueron fichas bibliográficas que se sustentaron en artículos de periódicos, revistas, folletos, boletines y obras de escritores Líbanenses. Se consultaron entidades como el DANE, la Alcaldía Municipal, Planeación, Biblioteca Municipal y entrevistas con personalidades que han sido protagonistas en el desarrollo de la industria del Líbano Tolima. A través de la Investigación se puede evidenciar que la historia del desarrollo de la Industria del Líbano, se divide en tres etapas fundamentales que son: Primera Etapa El Florecimiento de un nuevo cultivo-El Café- Segunda etapa La Violencia, Tercera Etapa La Reconstrucción. La investigación esta proyectada a dejar inquietudes sobre el florecimiento de la Industria del Líbano, ya que conociendo sus etapas deja buenas bases para iniciar proyectos que quieran sacar avante la industria del Municipio, porque posee la infraestructura.This work specifies some of the causes that impacted in the failure of the industrial development of the Líbano Tolima. The investigation is documental framed inside the descriptive, exploratory type, explanatory. One kept in mind the biggest population to 70 years, they interviewed to 35 people that gave information to near the process of the industry through the different stages framed in the investigation. The used instruments were bibliographical records that were sustained in articles of newspapers, magazines, pamphlets, bulletins and writers' works Líbanenses. Entities were consulted like the one DANE, the Municipal Governorship, Planeación, Municipal Library and you interview with personalities that have been main characters in the development of the industry of the Líbano Tolima. Through the Investigation you can evidence that the history of the development of the Industry of the Líbano, is divided in three fundamental stages that are: First Stage The Bloom of a new one cultivation-the Coffee - Second stage The Violence, Third Stage The Reconstruction. The investigation this projected to leave restlessness on the bloom of the Industry of the Líbano, since knowing their stages leaves good bases to begin projects that want to take out avante the industry of the Municipality, because it possesses the infrastructure

Are block copolymer worms more effective Pickering emulsifiers than block copolymer spheres?

RAFT-mediated polymerisation-induced self-assembly (PISA) is used to prepare six types of amphiphilic block copolymer nanoparticles which were subsequently evaluated as putative Pickering emulsifiers for the stabilisation of n-dodecane-in-water emulsions. It was found that linear poly(glycerol monomethacrylate)–poly(2-hydroxypropyl methacrylate) (PGMA–PHPMA) diblock copolymer spheres and worms do not survive the high shear homogenisation conditions used for emulsification. Stable emulsions are obtained, but the copolymer acts as a polymeric surfactant; individual chains rather than particles are adsorbed at the oil–water interface. Particle dissociation during emulsification is attributed to the weakly hydrophobic character of the PHPMA block. Covalent stabilisation of these copolymer spheres or worms can be readily achieved by addition of ethylene glycol dimethacrylate (EGDMA) during the PISA synthesis. TEM studies confirm that the resulting cross-linked spherical or worm-like nanoparticles survive emulsification and produce genuine Pickering emulsions. Alternatively, stabilisation can be achieved by either replacing or supplementing the PHPMA block with the more hydrophobic poly(benzyl methacrylate) (PBzMA). The resulting linear spheres or worms also survive emulsification and produce stable n-dodecane-in-water Pickering emulsions. The intrinsic advantages of anisotropic worms over isotropic spheres for the preparation of Pickering emulsions are highlighted. The former particles are more strongly adsorbed at similar efficiencies compared to spheres and also enable smaller oil droplets to be produced for a given copolymer concentration. The scalable nature of PISA formulations augurs well for potential applications of anisotropic block copolymer nanoparticles as Pickering emulsifiers

In situ SAXS studies of a prototypical RAFT aqueous dispersion polymerization formulation: monitoring the evolution in copolymer morphology during polymerization-induced self-assembly

Small-angle X-ray scattering (SAXS) is used to characterize the in situ formation of diblock copolymer spheres, worms and vesicles during reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate at 70 °C using a poly(glycerol monomethacrylate) steric stabilizer. 1H NMR spectroscopy indicates more than 99% HPMA conversion within 80 min, while transmission electron microscopy and dynamic light scattering studies are consistent with the final morphology being pure vesicles. Analysis of time-resolved SAXS patterns for this prototypical polymerization-induced self-assembly (PISA) formulation enables the evolution in copolymer morphology, particle diameter, mean aggregation number, solvent volume fraction, surface density of copolymer chains and their mean inter-chain separation distance at the nanoparticle surface to be monitored. Furthermore, the change in vesicle diameter and membrane thickness during the final stages of polymerization supports an ‘inward growth’ mechanism

Polymerization-Induced Self-Assembly of Block Copolymer Nano-objects via RAFT Aqueous Dispersion Polymerization

In this Perspective, we discuss the recent development of polymerization-induced self-assembly mediated by reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization. This approach has quickly become a powerful and versatile technique for the synthesis of a wide range of bespoke organic diblock copolymer nano-objects of controllable size, morphology, and surface functionality. Given its potential scalability, such environmentally-friendly formulations are expected to offer many potential applications, such as novel Pickering emulsifiers, efficient microencapsulation vehicles, and sterilizable thermo-responsive hydrogels for the cost-effective long-term storage of mammalian cells

RAFT polymerization of hydroxy-functional methacrylic monomers under heterogeneous conditions: effect of varying the core-forming block

Statistical copolymerization of a 1 : 1 molar ratio of a water-miscible monomer (2-hydroxyethyl methacrylate, HEMA) with a water-immiscible monomer (4-hydroxybutyl methacrylate, HBMA) has been conducted in water via reversible addition–fragmentation chain transfer (RAFT) polymerization using a water-soluble poly(glycerol monomethacrylate) macromolecular chain transfer agent (PGMA macro- CTA). In principle, such a hybrid formulation might be expected to be intermediate between RAFT dispersion polymerization and RAFT emulsion polymerization. Under such circumstances, it is of particular interest to examine whether both monomers are actually consumed and, if so, whether their rates of reaction are comparable. Given the water-solubility of both the PGMA macro-CTA and the free radical azo initiator, it is perhaps counter-intuitive that the water-immiscible HBMA is initially consumed significantly faster than the water-miscible HEMA, as judged by 1H NMR studies of this copolymerization. However, both comonomers are eventually almost fully consumed at 70 �C. A detailed phase diagram has been constructed for this RAFT formulation that enables reproducible syntheses of various pure copolymer morphologies, including spheres, worms and vesicles. It is emphasized that utilizing a 1 : 1 HEMA/HBMA molar ratio produces a core-forming statistical copolymer block that is isomeric with the poly(2-hydroxypropyl methacrylate) (PHPMA) core-forming block previously synthesized via RAFT aqueous dispersion polymerization (see A. Blanazs et al., Macromolecules, 2012, 45, 5099–5107). Hence it is rather remarkable that the thermo-responsive behavior of PGMA–P(HBMA-stat-HEMA) statistical block copolymer worm gels differs qualitatively from that exhibited by PGMA–PHPMA diblock copolymer worm gels

Élaboration de nanoparticules fluorescentes à base de BODIPY par polymérisation RAFT en miniémulsion : synthèse, caractérisation et fonctionnalisation de surface

This PhD work presents the synthesis of fluorescent nanoparticles (FNP) via a RAFT miniemulsion polymerisation and the analysis of their fluorescence properties. The core of the FNPs is a copolymer of styrene and a BODIPY monomer, and the shell, which is biocompatible and functionnalisable, is made of poly(ethylene oxyde) and poly(acrylic acid). First of all, the synthesis' optimisation of those FNPs is presented, and to the development of a one-pot process. Then, the fluorescence properties of those FNPs are studied, especially the impact of the BODIPY monomer concentration on the formation of non or weakly fluorescent aggregates. In order to change the FNP's spectroscopics properties (fluorescent quantum yield and emission wavelength), novel fluorescent BODIPY monomers have been synthesized. Those monomers presents either some bulky aromatics substituants, either variable polymerisable functions. The FNPS's hydrophilic shell has also been modified to get different distributions of the acrylic acid and ethylene oxyde units in the polymer chains of the FNPs' surface. Those new FNPs are also synthesized via a one-pot process. At last, molecules bearing an amine function (fluorescent dyes, proteins) have been grafted onto the differents FNPs' shell via a peptid coupling reaction on the carboxylic acid functions. As such, some pH ratiometric nano-sensors have been developped.Les travaux de cette thèse présentent la synthèse par une polymérisation RAFT en miniémulsion de nanoparticules fluorescentes (NPFs) polymères à coeur BODIPY copolymérisé au styrène et à couronne hydrophile biocompatible et fonctionnalisable à base de poly(oxyde d'éthylène) et de poly(acide acrylique). Les propriétés de fluorescence de ces NPFs ont été étudiées par spectroscopie de fluorescence stationnaire et résolue en temps. L'élaboration de la synthèse de ce type de NPFs, et la mise au point d'un procédé "one-pot" sont présentés dans un premier temps. Ensuite, les propriétés spectroscopiques de ces NPFs sont étudiées, notamment l'influence de la concentration en monomères de BODIPY au coeur des NPFs pouvant mener à la formation d'agrégats peu ou pas fluorescents. Les propriétés spectroscopiques (longueur d'onde d'émission de fluorescence et rendement quantique) du coeur des NPFs ont été modulées. Cela est rendu possible en réalisant la synthèse de monomères de BODIPY portant des groupements aromatiques encombrés, ou présentant différentes fonctions polymérisables. La couronne hydrophile des NPFs a également été modifiée afin d'obtenir différentes répartitions des unités acide acrylique et oxyde d'éthylène dans les chaînes de copolymères en surface. Ces nouvelles NPFs sont également synthétisées par un procédé "one-pot". Enfin, des molécules à fonctions amine (fluorophores, protéines) ont été introduites dans la couronne hydrophile de ces diverses NPFs par une chimie de couplage peptidique sur les fonctions acides carboxyliques. Des nano-senseurs de pH ratiométriques ont ainsi pu être élaborés

Elaboration of BODIPY fluorescent nanoparticules via a RAFT polymerisation in miniemulsion : synthesis, characterisation and surface functionalisation

Les travaux de cette thèse présentent la synthèse par une polymérisation RAFT en miniémulsion de nanoparticules fluorescentes (NPFs) polymères à coeur BODIPY copolymérisé au styrène et à couronne hydrophile biocompatible et fonctionnalisable à base de poly(oxyde d'éthylène) et de poly(acide acrylique). Les propriétés de fluorescence de ces NPFs ont été étudiées par spectroscopie de fluorescence stationnaire et résolue en temps. L'élaboration de la synthèse de ce type de NPFs, et la mise au point d'un procédé "one-pot" sont présentés dans un premier temps. Ensuite, les propriétés spectroscopiques de ces NPFs sont étudiées, notamment l'influence de la concentration en monomères de BODIPY au coeur des NPFs pouvant mener à la formation d'agrégats peu ou pas fluorescents. Les propriétés spectroscopiques (longueur d'onde d'émission de fluorescence et rendement quantique) du coeur des NPFs ont été modulées. Cela est rendu possible en réalisant la synthèse de monomères de BODIPY portant des groupements aromatiques encombrés, ou présentant différentes fonctions polymérisables. La couronne hydrophile des NPFs a également été modifiée afin d'obtenir différentes répartitions des unités acide acrylique et oxyde d'éthylène dans les chaînes de copolymères en surface. Ces nouvelles NPFs sont également synthétisées par un procédé "one-pot". Enfin, des molécules à fonctions amine (fluorophores, protéines) ont été introduites dans la couronne hydrophile de ces diverses NPFs par une chimie de couplage peptidique sur les fonctions acides carboxyliques. Des nano-senseurs de pH ratiométriques ont ainsi pu être élaborés.This PhD work presents the synthesis of fluorescent nanoparticles (FNP) via a RAFT miniemulsion polymerisation and the analysis of their fluorescence properties. The core of the FNPs is a copolymer of styrene and a BODIPY monomer, and the shell, which is biocompatible and functionnalisable, is made of poly(ethylene oxyde) and poly(acrylic acid). First of all, the synthesis' optimisation of those FNPs is presented, and to the development of a one-pot process. Then, the fluorescence properties of those FNPs are studied, especially the impact of the BODIPY monomer concentration on the formation of non or weakly fluorescent aggregates. In order to change the FNP's spectroscopics properties (fluorescent quantum yield and emission wavelength), novel fluorescent BODIPY monomers have been synthesized. Those monomers presents either some bulky aromatics substituants, either variable polymerisable functions. The FNPS's hydrophilic shell has also been modified to get different distributions of the acrylic acid and ethylene oxyde units in the polymer chains of the FNPs' surface. Those new FNPs are also synthesized via a one-pot process. At last, molecules bearing an amine function (fluorescent dyes, proteins) have been grafted onto the differents FNPs' shell via a peptid coupling reaction on the carboxylic acid functions. As such, some pH ratiometric nano-sensors have been developped

Evaluation de facteurs motivant ou freinant la prise parentale de la température chez l'enfant avant de consulter un médecin

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF