RESUMEN
A biomimetic composite of nanohydroxyapatite (nHap) and semicrystalline polyamide 6,9 (PA 6,9) was synthesized by thermally induced phase separation. The nHap powder was dispersed in a polymer matrix with a low ratio ranging 1-10 wt %. The mean size of the nHap, determined by scanning electron microscopy (SEM) was approximately 100-200 nm (length), 40-60 nm (width). Physicochemical analyses were performed in order to characterize the PA 6,9 and nHap separately on the one hand, and the PA 6,9/nHap composites on the other hand. Differential scanning calorimetry (DSC) and dynamic mechanical analyses (DMA) have pointed out an optimization of the composite physical properties as a function of nHap content till a limit value of 5 wt %. Above this value, the mechanical properties decreased. Four main parameters have been found to influence the composite physical properties improvement: the fillers content, the physical structure of the polymeric matrix, the particles dispersion and the physical interaction strength between organic and inorganic phases. The dynamic mechanical properties of this biomimetic nanocomposite were compared with human cortical bone.
Asunto(s)
Materiales Biomiméticos/química , Durapatita/química , Nanocompuestos/química , Nylons/química , Materiales Biomiméticos/síntesis química , Huesos/química , Huesos/ultraestructura , Durapatita/síntesis química , Humanos , Nylons/síntesis química , Tamaño de la Partícula , Estrés MecánicoRESUMEN
La discromatopsia es un trastorno funcional, habitualmente heredado, cuya prevalencia en hombres es elevada (4,53% en nuestro estudio). Dado que puede motivar alteraciones en el rendimiento académico y posteriormente en la actividad laboral, su detección en la edad escolar debe considerarse importante. Ello requiere la aplicación de métodos específicos del cribado (AU)
Dyschromatopsia is a functional, usually inherited dysfunction with a high prevalence in males (4.53% in our study). Since it can affect academic performance and, later on, professional activity, screening school-age children for it should be considered important. This requires the application of specific methods of screening (AU)
Asunto(s)
Niño , Humanos , Oftalmopatías/diagnóstico , Oftalmopatías/prevención & control , Enfermedades Hereditarias del Ojo/diagnósticoRESUMEN
The referrals for urgent psychiatric treatment were studied systematically to improve our understanding of the acute forms of psychological distress in children and adolescents and the crisis situations which disrupt the usual relationships between the child and his family. During the last 12 months, 212 requests for urgent psychiatric opinion in children under 18 years of age were received. The following points were analyzed: --general: age, sex, geographical distribution of the patients and their families, present family conditions, socio-economic class, origin of the urgent referral; --psychological or psychopathological: presenting symptoms, organisation of the personality of the child or adolescent, previous psychological or psychiatric history; --practical: the emergency management, ulterior orientation. The authors conclude with some remarks on the possible lines of action in the emergency situations.
Asunto(s)
Intervención en la Crisis (Psiquiatría) , Trastornos Mentales/terapia , Enfermedad Aguda , Adolescente , Factores de Edad , Niño , Preescolar , Femenino , Humanos , Masculino , Trastornos Mentales/epidemiología , Relaciones Padres-Hijo , Factores Sexuales , Factores SocioeconómicosRESUMEN
From our experience in the pedopsychiatric emergency unit at the Salpêtrière Hospital, we discuss the concept of psychiatric emergency in children and adolescents. In 90% of cases, patients are adolescents aged 14 to 18 years. The acting out and the ensuing emergency consultation seem to be a propitious time for establishing a relationship with the adolescent, meeting his difficulties from a psychological rather than affective standpoint and instituting an exchange with the family.