RESUMEN
Grit blasting is a surface plastic deformation technique aimed to increase the surface area available for bone/implant apposition, which contributes to improve fixation and mechanical stability of Ti-6Al-4V implants. Besides roughening, grit blasting also causes surface contamination with embedded grit particles and subtle subsurface microstructural changes that, although does not challenge their biocompatibility, might influence other surface dominated properties like corrosion and ion release. Additional benefits are expected due to the induced compressive residual stresses, hence enhancing fatigue strength. The net effect depends on the type of particles used for blasting, but also on the amount of the subsurface cold work associated to the severe surface plastic deformation. In this work we study the potential of the non-contacting and contacting thermoelectric power (TEP) measurements in the analysis of the global changes induced in the Ti6Al4V when blasting the alloy with Al2O3 or ZrO2 particles, which yields a coarse and a fine rough surface, respectively. To reveal the effect of residual stresses, a set of specimens were thermally treated. The study proves that the non-contacting technique is more sensitive to the presence of residual stresses, whereas the contact technique is strongly influenced by the grain size refinements, work hardening and changes in solute.
Asunto(s)
Electricidad , Ensayo de Materiales/métodos , Temperatura , Titanio/química , Aleaciones , Electrones , Dureza , Difracción de Rayos XRESUMEN
INTRODUCTION: Borderline personality disorder (BPD) is typically characterized by severe affective dysregulation leading to impulsive behaviors. Accordingly, preliminary data suggest the hypothesis that BPD patients could have a specific and altered pattern of subjective emotional response to stimuli. The nature of the emotional response in BPD can be compared with other affective disorders and provide further insight on the nosological proximity with other psychiatric disorders. METHODS: Subjective emotional response was investigated in 19 patients with DSM-IV BPD with no current depressive episode and in 19 healthy control subjects by using the International Affective Picture System (IAPS). The intensity of arousal, valence and dominance was rated in response to 60 images categorized as pleasant, unpleasant and neutral by using a self-assessment instrument. ANOVA of multiple factors was used for between-groups comparisons. RESULTS: The obtained pattern showed that BPD patients considered the unpleasant and neutral images as less aversive than controls, but the activation that these images induced was higher. Patients showed significantly greater arousal than controls for unpleasant and neutral images (p<0.05) but presented greater valence (more positive emotion) for these images (p<0.05). In addition, BPD patients showed lower dominance (greater insecurity and dyscomfort) for positive images (p<0.05). CONCLUSIONS: The subjective emotional response pattern of BPD patients suggests a trait of vulnerability to pleasant stimuli and is similar to the pattern found in depressive patients in previous studies. This supports the evidence that BPD could in part be related with the spectrum of the affective temperament and affective disorders.
Asunto(s)
Trastorno de Personalidad Limítrofe/psicología , Depresión/psicología , Trastornos Disruptivos, del Control de Impulso y de la Conducta/psicología , Emociones , Adolescente , Adulto , Agresión , Nivel de Alerta/fisiología , Estudios de Casos y Controles , Trastorno Depresivo , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Humanos , Masculino , Autoevaluación (Psicología) , Adulto JovenRESUMEN
The purpose of this study was to determine if different methods for average bioequivalence in high variability drugs coincide or not in their conclusions when applied to the same dataset, and to discuss the method validity and reliability of the conclusions. Different approaches for the evaluation of average bioequivalence were applied to the results of a bioavailability trial on the diuretic drug Furosemide. These methods included widening the bioequivalence limits according to regulatory recommendations, scaling the limits and scaling the bioequivalence statistic, jointly with evaluating alternative bioavailability measures. The methods to establish the bioequivalence limits were also combined with some alternative methods to construct confidence intervals. The decision on bioequivalence depends much more on the bioavailability measures than on the statistical approach. The reliability of the final decision lies mainly in the interpretation of these measures and on the special characteristics of each drug.
Asunto(s)
Diuréticos/farmacocinética , Furosemida/farmacocinética , Adulto , Área Bajo la Curva , Disponibilidad Biológica , Cromatografía Líquida de Alta Presión , Estudios Cruzados , Diuréticos/metabolismo , Femenino , Furosemida/metabolismo , Humanos , Masculino , Modelos Estadísticos , Ensayos Clínicos Controlados Aleatorios como Asunto , Equivalencia TerapéuticaRESUMEN
Unboiled, unchlorinated drinking water is known to have been associated with epidemic transmission of cholera in Trujillo, Peru, in February 1991. In September of that same year, chlorination of the main water supply system was begun. Water quality in Trujillo at the central level is monitored at dams and principal distribution points, but the effects of this surveillance on the quality of the water distributed are not known. In order to evaluate water quality in the residential areas of Trujillo, water samples were collected in February 1993 from 30 systematically selected houses. The chlorine levels in the samples were measured, and cultures for coliform bacteria were done. The free chlorine concentration varied from 0 to 1.5 mg/L (median = 0.4 mg/L). No free chlorine was detected in 5 samples (17%), and in 14 (47%) the concentrations were less than 0.4 mg/L. Coliforms were found in 16 samples (53%), but none were fecal coliforms. These results demonstrate the wide variability in chlorine concentrations in the municipal water that is distributed to dwellings. This variability, together with the need to store drinking water in the house because of shortages, supports the recommendation of the Ministry of Health that residents should treat drinking water in their homes. The simple sampling framework employed in this study provided a rapid evaluation of the quality of municipal water supplied to consumers. Similar studies could be carried out easily in other metropolitan areas where water quality is suspect, in order to rapidly obtain essential information on water quality at the level of the consumer.
Asunto(s)
Cólera/prevención & control , Abastecimiento de Agua/normas , Cloro/análisis , Cólera/transmisión , Monitoreo del Ambiente , Humanos , Perú , Control de Calidad , Microbiología del Agua , Abastecimiento de Agua/análisisRESUMEN
OBJECTIVE: Ataque de nervios ("attack of nerves") is an illness category used frequently by Hispanic individuals to describe one or more particular symptom complexes. A review of the literature on ataque suggested some overlap with panic disorder. This study investigated the overlap with panic disorder as well as other DSM-III-R axis I disorders. METHOD: Hispanic subjects seeking treatment at an anxiety disorders clinic (N = 156) were assessed with a specially designed questionnaire for self-report of ataque de nervios and panic symptoms and with structured or semistructured psychiatric interviews for axis I disorders. RESULTS: Seventy percent of the subjects reported at least one ataque de nervios; 80% of these were female, whereas 57% of the group without these attacks were female. There were no differences in DSM-III-R diagnoses between the groups with and without ataque de nervios. Ataque was frequently associated with one or more anxiety and affective disorders, including panic disorder, generalized anxiety disorder, recurrent major depression, and anxiety not otherwise specified. Of the 45 subjects with both ataque de nervios and primary panic disorder, 80% appeared to have labeled panic disorder as ataque. Ataque de nervios was associated with panic symptoms even in subjects without panic disorder, but the self-reporting of ataque conveyed additional clinical information about the subjects with panic disorder. Ataque de nervios was similar in frequency and symptoms among subjects of Dominican and Puerto Rican origin. CONCLUSIONS: Ataque de nervios overlaps with panic disorder but is a more inclusive construct. Further study of its interrelation with axis I disorders is needed.