RESUMEN
Cognitive changes in aging include working memory (WM) decline, which may hamper language comprehension. An increase in WM demands in older adults would probably provoke a poorer sentence processing performance in this age group. A way to increase the WM load is to separate two lexical units in an agreement relation (i.e., adjective and noun), in a given sentence. To test this hypothesis, event-related potentials (ERPs) were collected from Spanish speakers (30 older adults, mean age = 66.06 years old; and 30 young adults, mean age = 25.7 years old) who read sentences to detect grammatical errors. The sentences varied with regard to (1) the gender agreement of the noun and adjective, where the gender of the adjective either agreed or disagreed with the noun, and (2) the WM load (i.e., the number of words between the noun and adjective in the sentence). No significant behavioral differences between groups were observed in the accuracy of the response, but older adults showed longer reaction times regardless of WM load condition. Compared with young participants, older adults showed a different pattern of ERP components characterized by smaller amplitudes of LAN, P600a, and P600b effects when the WM load was increased. A smaller LAN effect probably reflects greater difficulties in processing the morpho-syntactic features of the sentence, while smaller P600a and P600b effects could be related to difficulties in recovering and mapping all sentence constituents. We concluded that the ERP pattern in older adults showed subtle problems in syntactic processing when the WM load was increased, which was not sufficient to affect response accuracy but was only observed to result in a longer reaction time.
RESUMEN
To the best of our knowledge, this paper outlines for the first time high adhesion and hybrid irreversible/reversible microfluidic devices fully composed of polydimethylsiloxane (PDMS). These chips were fabricated by the sandwich bonding (SWB), a method that was recently deployed by our group. SWB offers simple, fast, and low cost operation requiring only a laboratory oven. The devices showed burst pressures of up to 4.5 MPa. This value is more than tenfold the pressures withstood by the full-PDMS chips described in literature. In terms of the reversible behavior, the ability for disassembling the chip slides is crucial in research and development stages, especially when the device integrates high-cost components or harsh cleaning steps are needed. Following successive steps of detachment and bonding, the channels still withstood high pressures of approximately 1.8 MPa. Finally, the emulsification of corn oil 4.0% w/w to polyglycerol polyricinoleate with 10.0 µmol L-1 rhodamine B aqueous solution was realized to show the relevance in enhancing the flow rate in microfluidics. Such experiment was conducted at total flow rates of 0.8-160.0 µL min-1. The decrease in size and polydispersity of the droplets was observed at increasing flow rates. Monodisperse emulsions were achieved only at 160.0 µL min-1.
RESUMEN
Resumen - Los estudios clínicos randomizados detenidos precozmente por beneficio son cada vez más frecuentes en la literatura médica. La detención precoz se fundamenta en la necesidad ética de ofrecer rápidamente una intervención beneficiosa a toda la población en riesgo, especialmente a los pacientes que son parte de grupo control del estudio. A pesar que la detención se fundamenta en análisis que demuestran beneficio estadísticamente significativo, se sabe que los estudios truncados precozmente tienen riesgo de detectar diferencias que realmente no existen. Este fenómeno se produce porque habitualmente estos estudios son de pequeñotamaño muestral y están sustentados en análisis estadísticos repetitivos, realizados a medida que se reclutan los pacientes. El lectordebe ser capaz de detectar estos estudios e identificar las herramientas para disminuir el riesgo de error y sesgo. El objetivo de la presente revisión es dar a conocer las herramientas disponibles para disminuir el riesgo, las estrategias estadísticas para sostener una adecuada detención temprana de un estudio, los comités de monitorización externa de los datos, la evidencia que sustentan estas afirmaciones y las iniciativas que se están llevando a cabo para cuantificar el riesgo y eventualmente ofrecer una solución.(AU)
Early stopping by benefit of randomized clinical studies are increasingly frequent in the medical literature. The early detection is based on the ethical need to quickly provide a beneficial intervention to the entire population at risk, particularly to patients who are part of study control group. Although the arrest was based on analyzes that show statistically significant benefit, it is known that early studies truncated have the risk to detect differences that do not exist. This phenomenon occurs because usually these studies have small sample size and are supported by repetitive statistical analyzes performed as patients are recruited. The reader should be able to detect these studies and identify tools to reduce the risk of error and bias. The aim of this review is to present the tools available to reduce risk, the statistical strategies to sustain an adequate early detection of an external monitoring data study committee, the evidence supporting these statements and initiatives that are being carried out to quantify the risk and eventually offer a solution.(AU)