La non-évidence de la souffrance :<br />De la psychose maniaco-dépressive vers l'aboulie.

Le syndrome maniaco-dépressif est ici analysé, dans une discussion avec les perspectives psychiatriques et psychanalytiques, comme une « aboulie », un « éclatement » du projet pulsionnel. Le maniaco-dépressif reste capable d'impulsion (d'affect), et il reste capable de se restreindre et de s'autoriser, mais dans tous les cas, qu'il soit dans un « épisode » « maniaque », « dépressif » ou « mixte », tout se passe comme si la volonté restait dispersée et inconstante. Il est donc discuté épistémologiquement l'intérêt de l'hypothèse d'un trouble de la pulsion pour avancer dans la compréhension de l'antagonisme apparent du syndrome maniaco-dépressif. La pulsion pourrait être définie, dans cette perspective, comme un contour (une « Gestalt ») d'impulsions, déterminant normalement la direction d'un intérêt électif. De même que la Gestaltisation perceptive est un intermédiaire nécessaire entre la sensation élémentaire et la structuration langagière, comme en témoigne l'agnosie, la pulsion pourrait être un intermédiaire nécessaire entre l'impulsion élémentaire (ou l'émotion, ou l'affect) et le contrôle éthique

À propos de la langue et de l'altérité : une observation clinique de « trouble de la mémoire<br />sémantique »

This clinical contribution aims to attract the attention of linguists and psychoanalytic or psychiatric clinicians to a neurological syndrome which is not well known outside the field of neuropsychology, where it is called “semantic memory disorder”. This disorder is of great interest about the issues of social language, subject, and relatedness (“otherness”). This syndrome is characterized by a peculiar misunderstanding and relational difficulties of / with others, and these difficulties appear also in the apprehension of language, knowledge and events. These peculiar difficulties are currently best characterized by a egocentric or strictly idiomatic appraisal of world and relationship, as the patient can refer objects, words, and so on, only through his own biographical and immediate experience. Thus, all experience is apprehended through an obligatory “auto-centration”. The clinical observation detailed in this work supports a defect of relatedness itself (or “otherness”). The subject cannot “abstract himself from himself”, or “decentralize” himself from his own experience, to integrate and access a distinct point of view. Although this analysis is convergent with the neuropsychological distinction between “episodic” and “semantic” memory, it enlarges the perspective to the process of “relatedness” or “otherness”Cette contribution clinique veut attirer l'attention des linguistes et des cliniciens enpsychopathologie sur un syndrome d'origine neurologique peu connu en dehors du milieu de laneuropsychologie où il est nommé « trouble de la mémoire sémantique ». Sans entrer dans le problèmede l'étiologie – rappelons juste que Freud en 1888 n'hésitait pas à dire que l'aphasie, trouble dulangage d'origine neurologique, était un trouble psychique –, ce trouble est d'un intérêt indéniablepour la conception de la langue, du sujet, plus précisément de l'altérité.Ce syndrome se caractérise de manière générale par une « incompréhension » particulière desautres et par des difficultés relationnelles avec les autres ; cette incompréhension et ces difficultésrelationnelles se manifestent également dans l'appréhension de la langue, du savoir, des choses et desévénements. Pour caractériser cette incompréhension et ce mode relationnels particuliers, ilscorrespondent à une appréhension strictement idiosyncrasique du monde et de la relation, et semanifestent dès que le patient ne peut directement référer les mots, les choses, les paroles etc. à sapropre expérience biographique vécue, à sa propre situation immédiate. Toute intervention et toutecompréhension du patient se font donc par le biais d'une autocentration incontournable.L'analyse qui en est faite ici, à partir d'une observation clinique caractéristique détaillée, est qu'ils'agit d'un trouble de l'altérité, se répercutant, entre autres, sur la langue, le savoir et l'interlocution. Ilsemble y avoir littéralement disparition du sujet en tant qu'être social pouvant se « détacher » ou« s'abstraire » de lui-même et de son propre vécu immédiat pour intégrer et accéder à un « rôle », un« point de vue » différencié d'autrui. Cette présentation et cette analyse se démarquent relativementdes interprétations neuropsychologiques qui se font en terme de « trouble de la mémoiresémantique » ; une perspective centrée sur les processus de l'altérité, de la personne et de la capacitésociale, pour surprenant que cela puisse paraître eu égard à l'étiologie, paraît pertinente

Le langage : une réalité tétramorphe et paradoxale

Cette réflexion s'effectue dans le cadre de l'anthropologie clinique proposée par Jean Gagnepain et questionne le rapport entre « constructivisme et relativisme », intitulé “officiel” de cette première rencontre. L'anthropologie clinique se donne pour objet le fonctionnement de la rationalité humaine à partir du langage et n'est pas exactement une théorie “du” langage, mais une théorie de la rationalité, elle-même nécessitée par le caractère surdéterminé des « mots et des choses », ou de ce qu'on appelle, ordinairement, le langage et le réel. Cette approche explicative de la rationalité humaine se caractérise par un double mouvement de formalisation théorique et de formalisation clinique des pathologies, le modèle se prolongent expérimentalement dans une nosographie systématique. Ce travail comporte trois parties : nous allons successivement tenter de montrer que le langage est une réalité paradoxale, puis une réalité tétramorphe et, enfin, une réalité cliniquement expérimentable, notamment à travers les exemples contrastés de l'aphasie et de l'agnosie

Shape modulation of squaramide-based supramolecular polymer nanoparticles

We report the synthesis and self-assembly of a library of squaramide-based bolaamphiphiles with variable hydrophobic and hydrophilic domain sizes, consisting of varied aliphatic chains (n = 2 to 12 methylene repeat units) and linear oligo(ethylene glycol) (m = 11 to 36 repeat units), to understand their effect on the formation of supramolecular polymer nanoparticles. Systematic variation of the hydrophobic chain length show that a minimum hydrophobic domain is required to shield the squaramide units from water when a constant hydrophilic domain is maintained for self-assembly. By contrast, significant increases to the hydrophilic chain length of the bolaamphiphile, while keeping the hydrophobic domain constant, results in a transition from fibrillar to spherical nanoscale objects with an alteration in the aggregation mode of the monomers likely due to steric constraints of the oligo(ethylene glycol) chains. By understanding the self-assembly space achievable for these squaramide-based bolaamphiphiles through examining the interplay between various monomer features, we show their distinct effects on the formation of self-assembled nanoparticles with possibilities to modulate their shape and size in water for future applications in the biomedical area.</p

Enzymatic Approach in Calcium Phosphate Biomineralization: A Contribution to Reconcile the Physicochemical with the Physiological View

Biomineralization is the process by which organisms produce hard inorganic matter from soft tissues with outstanding control of mineral deposition in time and space. For this purpose, organisms deploy a sophisticated &ldquo;toolkit&rdquo; that has resulted in significant evolutionary innovations, for which calcium phosphate (CaP) is the biomineral selected for the skeleton of vertebrates. While CaP mineral formation in aqueous media can be investigated by studying thermodynamics and kinetics of phase transitions in supersaturated solutions, biogenic mineralization requires coping with the inherent complexity of biological systems. This mainly includes compartmentalization and homeostatic processes used by organisms to regulate key physiological factors, including temperature, pH and ion concentration. A detailed analysis of the literature shows the emergence of two main views describing the mechanism of CaP biomineralization. The first one, more dedicated to the study of in vivo systems and supported by researchers in physiology, often involves matrix vesicles (MVs). The second one, more investigated by the physicochemistry community, involves collagen intrafibrillar mineralization particularly through in vitro acellular models. Herein, we show that there is an obvious need in the biological systems to control both where and when the mineral forms through an in-depth survey of the mechanism of CaP mineralization. This necessity could gather both communities of physiologists and physicochemists under a common interest for an enzymatic approach to better describe CaP biomineralization. Both homogeneous and heterogeneous enzymatic catalyses are conceivable for these systems, and a few preliminary promising results on CaP mineralization for both types of enzymatic catalysis are reported in this work. Through them, we aim to describe the relevance of our point of view and the likely findings that could be obtained when adding an enzymatic approach to the already rich and creative research field dealing with CaP mineralization. This complementary approach could lead to a better understanding of the biomineralization mechanism and inspire the biomimetic design of new materials

Enzymatic Approach in Calcium Phosphate Biomineralization: A Contribution to Reconcile the Physicochemical with the Physiological View

Biomineralization is the process by which organisms produce hard inorganic matter from soft tissues with outstanding control of mineral deposition in time and space. For this purpose, organisms deploy a sophisticated “toolkit” that has resulted in significant evolutionary innovations, for which calcium phosphate (CaP) is the biomineral selected for the skeleton of vertebrates. While CaP mineral formation in aqueous media can be investigated by studying thermodynamics and kinetics of phase transitions in supersaturated solutions, biogenic mineralization requires coping with the inherent complexity of biological systems. This mainly includes compartmentalization and homeostatic processes used by organisms to regulate key physiological factors, including temperature, pH and ion concentration. A detailed analysis of the literature shows the emergence of two main views describing the mechanism of CaP biomineralization. The first one, more dedicated to the study of in vivo systems and supported by researchers in physiology, often involves matrix vesicles (MVs). The second one, more investigated by the physicochemistry community, involves collagen intrafibrillar mineralization particularly through in vitro acellular models. Herein, we show that there is an obvious need in the biological systems to control both where and when the mineral forms through an in-depth survey of the mechanism of CaP mineralization. This necessity could gather both communities of physiologists and physicochemists under a common interest for an enzymatic approach to better describe CaP biomineralization. Both homogeneous and heterogeneous enzymatic catalyses are conceivable for these systems, and a few preliminary promising results on CaP mineralization for both types of enzymatic catalysis are reported in this work. Through them, we aim to describe the relevance of our point of view and the likely findings that could be obtained when adding an enzymatic approach to the already rich and creative research field dealing with CaP mineralization. This complementary approach could lead to a better understanding of the biomineralization mechanism and inspire the biomimetic design of new materials

Le "syndrome sémantique-pragmatique": Dysphasie, autisme ou "dysharmonie psychotique"?

International audienc

Controlling nanoparticles dispersion in ionic liquids by tuning the pH

International audienceAbstractHypothesisGetting colloidally stable dispersions of nanoparticles in ionic liquids is a challenging task. Indeed, long-range electrostatic repulsions often involved in molecular solvents are screened in ionic liquids and cannot counterbalance the interparticle attractions. Using a polyelectrolyte coating should provide a good stabilisation of the nanoparticles. Investigating the role of the polyelectrolyte charge on the dispersion state should yield to a better comprehension of the stabilisation mechanisms.ExperimentsPolyacrylate coated maghemite nanoparticles were transferred from water to ethylammonium nitrate, a protic ionic liquid, for various polymer chain length and nanoparticles size. Titrations of coated nanoparticles and of free polymer chains were performed in water and in ethylammonium nitrate. The dispersion state of the nanoparticles was monitored at different pH by small-angle X-ray scattering.FindingsPolyacrylate coating stabilised the nanoparticles in ethylammonium nitrate. However, reversible aggregation with the pH was observed. Surprisingly, this control was not directly related to the surface charge like in water but to the solvent quality for the polyelectrolyte. This study is the first report on the use of the pH to tune the dispersion state of nanoparticles in an ionic liquid. It provides a better understanding of the mechanisms responsible for colloidal stability in ionic liquids

Hyperthermia of Magnetic Nanoparticles: An Experimental Study of the Role of Aggregation

International audienceMagnetic hyperthermia is a promising tool as an adjuvant therapy for multimodal cancer treatment. However, the heating efficiency of magnetic nanoparticles in biological conditions is not yet fully understood, especially regarding their dispersion state. In this work, dynamic light scattering (DLS) and hyperthermia experiments were coupled to highlight the role of the aggregation of iron oxide nanoparticles on their heating properties induced by an alternating magnetic field. Bare, poly(acrylic acid), and poly(acrylic acid-co-maleic acid) coated nanoparticles were studied. More precisely, the interparticular interactions were investigated by varying the ionic strength and the pH. Our results show that the specific loss power (SLP) of nanoparticles in small and loose aggregates is similar to that of well dispersed nanoparticles while the formation of large and dense aggregates observed by DLS can be correlated to a decrease of the SLP of the nanoparticles. However, at intermediate aggregation states, DLS experiments alone do not allow to fully comprehend the heating properties of magnetic nanoparticles. Small angle X-ray scattering experiments (SAXS) were performed to get information about the inner structure of the aggregates: the closer the nanoparticles in the aggregates, the less they heat the surrounding medium. These results shed a new light on the negative influence of the interparticular interactions in aggregates on the particles heating efficiency