Market power and voluntary land redistribution

Inequality in land ownership remains a major issue in many developing countries, such as Brazil, Colombia, and South Africa. Donors advocate a new model of "willing-buyer/willing-seller\", market-led land redistribution, but actual redistribution has fallen short of expectations. Little effort has been made so far to formalize the obstacles to market-led land redistribution. In this paper, we show that oligopolistic owner-producers may resist land sales to poorer candidate-buyers not only because they have a lower willingness to pay for land but also because the entry of poorer entrants threatens tacit collusion

Magnetic tubules

International audienceDispersion of tubules made of diacetylenic phospholipids (DC8,9PC), in aqueous colloidal dispersions of magnetic nanoparticles is studied as a function of the sign of particles surface charges. In every case the tubule-vesicle transition temperature is decreased by the presence of the magnetic nanoparticles. Electrophoresis experiments on the tubules in pure water permits to conclude on a negative apparent surface charge. We study the magnetic response of the system to a static or stationary rotating field and to a magnetic field gradient. These experiments reveal an excess or a lack of magnetic permeability between tubules and the surrounding medium. Electron microscopy confirms these results showing an electrostatic interaction between the phospholipidic bilayer and the magnetic particles

Oblate-Prolate Transition of Ellipsoidal Giant Magnetoliposomes: Experiments Showing an Anisotropic Spontaneous Curvature (Chapter 11)

International audienceThis chapter contains sections titled:IntroductionLiposome PreparationObservationsAnalysis of Deformations Under a Magnetic FieldInterpretatio

Designing magnetic composite materials from aqueous magnetic fluids

International audienceIn this paper, we report on how to take advantage of good knowledge of both the chemistry and the stability of an aqueous magnetic colloidal suspension to realize different magnetic composites. The osmotic pressure of the magnetic nanoparticles is set prior to the realization of the composite to a given value specially designed for the purpose for each hybrid material: magnetic particles in polymer networks, particles as probes for studying the structure of clay suspensions and shape modification of giant liposomes.First, we show that the introduction of magnetic particles in polyacrylamide gels enhances their Young modulus and reduces the swelling caused by water. The particles cause both a mechanical and an osmotic effect. The latter is strongly dependent on the ionic strength and is attributed to an attraction between particles and the polymeric matrix.In the second part, we determine the microscopic structure of suspensions of laponite as a function of concentration, by combining SANS and magneto-optical experiments with the probes. This study requires conditions suitable for including the magnetic particles as probes without disturbing the clay suspensions.The third part presents giant magnetoliposomes, which encapsulate magnetic nanoparticles. Shape transitions are obtained with either a magnetic field or an osmotic stress

Recent insights in magnetic hyperthermia: From the “hot-spot” effect for local delivery to combined magneto-photo-thermia using magneto-plasmonic hybrids

International audienceMagnetic hyperthermia which exploits the heat generated by magnetic nanoparticles (MNPs) when exposed to an alternative magnetic field (AMF) is now in clinical trials for the treatment of cancers. However, this thermal therapy requires a high amount of MNPs in the tumor to be efficient. On the contrary the hot spot local effect refers to the use of specific temperature profile at the vicinity of nanoparticles for heating with minor to no long-range effect. This magneto-thermal effect can be exploited as a relevant external stimulus to temporally and spatially trigger drug release.In this review, we focus on recent advances in magnetic hyperthermia. Indirect experimental proofs of the local temperature increase are first discussed leading to a good estimation of the temperature at the surface (from 0.5 to 6 nm) of superparamagnetic NPs. Then we highlight recent studies illustrating the hot-spot effect for drug- release. Finally, we present another recent strategy to enhance the efficacity of thermal treatment by combining photothermal therapy with magnetic hyperthermia mediated by magneto-plasmonic nanoplatforms

Preparation and swelling of hydrophilic magnetic microgels

Hydrophilic magnetic microgels were synthesized by a free-radical polymerization in inverse emulsion. Two sizes of magnetic microgels were obtained depending on the initial droplet size of the emulsion. As the polymer matrix is a hydrogel, the novelty of this paper is that the magnetic particles are incorporated from an aqueous magnetic fluid instead of an organic one. In this paper, we underline the physicochemical aspects necessary to control the proper dispersion of the magnetic particles in the polymer matrix. The size, the magnetic content and the swelling degree of micron-sized and sub-micron sized magnetic microgels are characterized

Hybrid Molecularly Imprinted Polymers: The Future of Nanomedicine?

International audienceMolecularly imprinted polymers (MIPs) have been widely used in nanomedicine in the last few years. However, their potential is limited by their intrinsic properties resulting, for instance, in lack of control in drug release processes or complex detection for in vivo imaging. Recent attempts in creating hybrid nanomaterials combining MIPs with inorganic nanomaterials succeeded in providing a wide range of new interesting properties suitable for nanomedicine. Through this review, we aim to illustrate how hybrid molecularly imprinted polymers may improve patient care with enhanced imaging, treatments, and a combination of both