Water dispersible microbicidal cellulose acetate phthalate film

BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP

P3HT-Based Solar Cells: Structural Properties and Photovoltaic Performance

Each year we are bombarded with B.Sc. and Ph.D. applications from students that want to improve the world. They have learned that their future depends on changing the type of fuel we use and that solar energy is our future. The hope and energy of these young people will transform future energy technologies, but it will not happen quickly. Organic photovoltaic devices are easy to sketch, but the materials, processing steps, and ways of measuring the properties of the materials are very complicated. It is not trivial to make a systematic measurement that will change the way other research groups think or practice. In approaching this chapter, we thought about what a new researcher would need to know about organic photovoltaic devices and materials in order to have a good start in the subject. Then, we simplified that to focus on what a new researcher would need to know about poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends (P3HT: PCBM) to make research progress with these materials. This chapter is by no means authoritative or a compendium of all things on P3HT:PCBM. We have selected to explain how the sample fabrication techniques lead to control of morphology and structural features and how these morphological features have specific optical and electronic consequences for organic photovoltaic device applications

Problèmes aux limites issus de la supraconductivité (estimations semi-classiques et comportement asymptotique des solutions)

Cette thèse est consacrèe à l'étude de plusieurs modèles de l'effet de proximité' dans le cadre de la thèorie de Ginzburg-Landau de la supraconductivité. Ces modèles proviennent des interfaces entre des supraconducteurs et des métaux normaux.Dans une première partie de cette thèse, nous estimons dans le régime semiclassique le bas du spectre d'un opérateur de Schrôdinger magnétique associé à une condition au bord du type Fourier (Robin), appelée dans ce contexte la condition au bord de de Gennes, et nous étudions également la localisation des états fondamentaux. Nous exhibons des cas où la condition au bord de de Gennes a des effets forts sur cette localisation.Dans une autre partie, nous construisons un problème spectral lié à l'apparition de la supraconductivité pour une fonctionnelle de Ginzburg-Landau généralisée ayant des coefficients discontinues, où le paramètre d'ordre' et le potentiel magnétique' sont définis dans l'espace entier. Pourle régime où le paramétre de Ginzburg-Landau est grand, nous estimons le champ surcritique corespondant au champ pour lequel les états normaux perdent leur stabilité. Dans d'autres régimes asymptotiques, nous retrouvons un développement limité déjà obtenu pour un autre modèle standard'.Dans la dernière partie, nous étudions de nouveau une fonctionnelle de Ginzburg-Landau généralisée mais dans le cas sans champ magnétique appliqué. Nous obtenons dans ce cas le comportement asymptotique du paramètre d'ordre pour le régime où le paramètre de Ginzburg-Landau est grand. Ceci montre en particulier que la supraconductivité persiste dans une bande mince dans le métal normal, près du bord du supraconducteur.This thesis is devoted to the study of various models for the proximity effect' in the frame work of the Ginzburg-Landau theory of superconductivity. These models arise in the situation when a superconductor is adjacent to a normal metal.In a first part of this thesis, we estimate in the semi-classical limit the ground state energy of a magnetic Schrôdinger operator associated to a Fourier (Robin) type boundary condition, called in this context the de Gennes boundary condition, and we study the localization of the ground states. We exhibit cases when the de Gennes boundary condition has strong effects on this localization.In another part, we formulate a spectral problem related to the onset of superconductivity for a generalized Ginzburg-Landau functional having discontinuous coefficients, where the order parameter and the magnetic potential are defined in the whole space In the regime when the Ginzburg-Landau parameter (of the superconducting material) is large, we estimate the critical applied magnetic field for which the normal state will lose its stability. In some asymptotic situations, we recover results related to the standard' Ginzburg-Landau model.In the final part, we study again a generalized Ginzburg-Landau functional in the case without an applied magnetic field. We determine in this case the asymptotic behavior of the order parameter in the regime when the Ginzburg-Landau parameter is large. This shows in particular that the superconductivity persists in a thin boundary sheath of the normal material, near the boundary of the superconductor.ORSAY-PARIS 11-BU Sciences (914712101) / SudocORSAY-PARIS 11-Bib. Maths (914712203) / SudocSudocFranceF