ABSTRACT
Artificial urinary devices are commonly employed to restore the lost functionalities of the urinary system, due to diseases, disfunctions or organ resections. However, the long-term operation of these devices in the urinary system is affected by encrustations. In this paper, three different nanostructured coatings, based on diamondlike carbon (DLC), molybdenum disulfide (MoS2) and Tungsten disulfide (WS2), were deposited on polydimethylsiloxane substrates, an elastomer suitable for coating different kinds of urinary devices, and tested in terms of resistance to urinary encrustations. DLC coatings were deposited using plasma enhanced-chemical vapor deposition (T < 180 °C), whereas MoS2 and WS2 coatings were achieved through self-assembly at room temperature. All coatings showed good adhesion and stability on PDMS substrate over one month, relatively small roughness, a strongly hydrophobic behavior, and low surface energy. After immersion in artificial urine formulations and continuous mechanical agitation for 4 weeks, WS2 coating resulted the most resistant to encrustations. This material had been never investigated in the urinary context. Our results pave the way to the adoption of WS2 coatings for developing long-lasting stable urinary devices.
ABSTRACT
Despite step-down inhibitory avoidance procedures that have been widely implemented in rats and mice to study learning and emotion phenomena, performance of other species in these tasks has received less attention. The case of the Mongolian gerbil is of relevance considering the discrepancies in the parameters of the step-down protocols implemented, especially the wide range of foot-shock intensities (i.e., 0.4-4.0 mA), and the lack of information on long-term performance, extinction effects, and behavioral patterning during these tasks. Experiment 1 aimed to (a) characterize gerbils' acquisition, extinction, and steady-state performance during a multisession (i.e., extended) step-down protocol adapted for implementation in a commercially-available behavioral package (Video Fear Conditioning System-MED Associates Fairfax, VT, USA), and (b) compare gerbils' performance in this task with two shock intensities - 0.5 vs. 1.0 mA-considered in the low-to-mid range. Results indicated that the 1.0 mA protocol produced more reliable and clear evidence of avoidance learning, extinction, and reacquisition in terms of increments in freezing and on-platform time as well as suppression of platform descent. Experiment 2 aimed to (a) assess whether an alternate protocol consisting of a random delivery of foot shocks could replicate the effects of Experiment 1 and (b) characterize gerbils' exploratory behavior during the step-down task (jumping, digging, rearing, and probing). Random shocks did not reproduce the effects observed with the first protocol. The data also indicated that a change from random to response-dependent shocks affects (a) the length of each visit to the platform, but not the frequency of platform descends or freezing time, and (b) the patterns of exploratory behavior, namely, suppression of digging and rearing, as well as increments in probing and jumping. Overall, the study demonstrated the feasibility of the extended step-down protocol for studying steady performance, extinction, and reacquisition of avoidance behavior in gerbils, which could be easily implemented in a commercially available system. The observation that 1.0 mA shocks produced a clear and consistent avoidance behavior suggests that implementation of higher intensities is unnecessary for reproducing aversive-conditioning effects in this species. The observed patterning of freezing, platform descents, and exploratory responses produced by the change from random to periodic shocks may relate to the active defensive system of the gerbil. Of special interest is the probing behavior, which could be interpreted as risk assessment and has not been reported in other rodent species exposed to step-down and similar tasks.
ABSTRACT
Impulsivity-related measures have been obtained using operantconditioning tasks. Although it has been suggested that impulsivity indices can also be obtained using the elevated plus-maze (EPM), an anxiety-related animal test, no studies have examined the relationship between anxiety-related variables in EPM and impulsivity-related indices obtained during operant conditioning. Correlations between EPM measures and performance in a 60-s fixed-interval schedule of reinforcement (FI 60-s) were established in this study. Seventeen female rats were exposed to the EPM before starting training in the FI 60-s schedule. A positive correlation was found between the percentage of time spent in the central area of the EPM and both the FI efficiency index and the inter-response times. In addition, these three measures were positively correlated within Factor 1 of a factor analysis. No correlations were observed between open-arms measures in EPM and operant performance. These results suggest that time in the central area of the EPM may be a useful index of impulsivity in rodents without a pre-determined trait of impulsivity.
Medidas relacionadas a impulsividad se han obtenido mediante tareas de condicionamiento operante. Aunque se ha sugerido que índices de impulsividad pueden ser también obtenidos usando el laberinto en cruz elevado (LCE), una prueba animal relacionada con ansiedad, ningún estudio ha examinado la relación entre las variables de ansiedad en el LCE e índices de impulsividad obtenidos durante condicionamiento operante. En este estudio se establecieron correlaciones entre medidas del LCE y el desempeño en un programa de reforzamiento de intervalo fijo 60-s (IF 60-s). Diecisiete ratas hembras fueron expuestas la LCE antes de iniciar el entrenamiento en el programa de IF 60-s. Se encontró una correlación positiva entre el porcentaje de tiempo de permanencia en el área central del LCE y tanto el índice de eficiencia como los tiempos entre respuestas en IF. Adicionalmente, estas tres medidas correlacionaron de forma positiva dentro del Factor 1 del análisis factorial. No se observaron correlaciones entre las medidas de los brazos abiertos del LCE y la ejecución operante. Los resultados sugieren que el tiempo en el área central del LCE podría ser un índice útil de impulsividad en roedores sin un perfil predeterminado de impulsividad.
ABSTRACT
El día 20 de agosto de 2010 la Fundación Universitaria Konrad Lorenz, la facultad de Psicología y el grupo de investigación en ciencias del comportamiento llevaron a cabo el Primer Encuentro Nacional de Comités para el Cuidado y Uso de Animales de Laboratorio. A continuación se presentan los resúmenes de las ponencias de los conferencistas nacionales e internacionales invitados a este encuentro.
