Development and application of a new Attended Field of View (AFOV) test

Purpose: An important challenge for eye care practitioners is meeting the needs of an ever-increasing elderly population. Standard vision tests are inadequate for determining performance in real life situations. One test that was developed to address this issue is the Attended Field of View (AFOV) test (Coeckelbergh et al, 2004). This test was designed to assess the functional field of view when people are allowed to make habitual head and eye movements. The original AFOV test is no longer available. This research seeks to develop a replacement AFOV test and to demonstrate its reliability as an assessment tool. Methods: Two groups of participants were recruited. The first group consisted of seven participants between the ages of 15-41 years. The second group consisted of seven participants between the ages of 59–79 years. All subjects had visual acuities equal or better than 20/25 and no history of visual field loss. A computer-generated display was observed from a 60cm distance. The display consisted of 24 white circles on a gray background and one open circle (target). The circles were organized with one circle in the centre and eight located radially at three eccentricities (4, 8, and 12 degrees). Participants were required to locate the target circle and identify the gap direction. A response was considered correct when both the location and gap direction were accurate. Using a weighted staircase method based on presentation time each location was evaluated independently. Viewing efficiency [log (1/threshold presentation time)] was obtained for each location. The data was analyzed using repeated measures ANOVA. Results: A comparison of viewing efficiency for the two age groups demonstrates that viewing efficiency is consistently lower for the older group at all three visits. The main effect of age was observed (F1,12=25.842;p=0.000). In the older group, a significant difference was found between the second and third visits. This difference was not found in the younger group. A main effect of eccentricity was found in both groups (F2,36=30.84;p<0.000), but no interaction was observed between eccentricity and group (F2,36=0.42;p=0.662). Viewing efficiency values in the older group were lower in all directions (main effect of age) (F1,96=150.36;p<0.000). Directional variations in viewing efficiency were observed showing higher values in the horizontal axes (directions Right and Left) than along the vertical axes (directions Up and Down) in both groups. A comparison of superior and inferior hemifield data shows consistent differences for both age groups. The superior hemifield (average of directions located superiorly to the horizontal axis) demonstrate higher viewing efficiency values (better performance) than the inferior hemifield. Conclusions: The use of the new AFOV test requires a practice time before its use in order to avoid the confound of a learning effect, but subsequent data is reliable in young people. The learning effect was more significant in older people and for this reason the use of the test should be preceded by a longer practice session in this population. When interpreting the results of this test one must account for eccentricity, direction, and age

Investigation of cannabis biomarkers and transformation products in waters by liquid chromatography coupled to time of flight and triple quadrupole mass spectrometry

11-Nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) is commonly selected as biomarker for the investigation of cannabis consumption through wastewater analysis. The removal efficiency of THC-COOH in wastewater treatment plants (WWTPs) has been reported to vary between 31% and 98%. Accordingly, possible transformation products (TPs) of this metabolite might be formed during treatment processes or in receiving surface water under environmental conditions. In this work, surface water was spiked with THC-COOH and subjected to hydrolysis, chlorination and photo-degradation (both ultraviolet and simulated sunlight) experiments under laboratory-controlled conditions. One hydrolysis, eight chlorination, three ultraviolet photo-degradation and seven sunlight photo-degradation TPs were tentatively identified by liquid chromatography coupled to quadrupole time-of-flight mass spectrometer (LC-QTOF MS). In a subsequent step, THC-COOH and the identified TPs were searched in wastewater samples using LC coupled to tandem mass spectrometry (LC–MS/MS) with triple quadrupole. THC-COOH was found in all influent and effluent wastewater samples analyzed, although at significant lower concentrations in the effluent samples. The removal efficiency of WWTP under study was approximately 86%. Furthermore, THC-COOH was also investigated in several surface waters, and it was detected in 50% of the samples analyzed. Regarding TPs, none were found in influent wastewater, while one hydrolysis and five photo-degradation (simulated sunlight) TPs were detected in effluent and surface waters. The most detected compound, resulting from sunlight photo-degradation, was found in 60% of surface waters analyzed. This fact illustrates the importance of investigating these TPs in the aquatic environment

Estudio de la resistividad eléctrica de distintos papeles de impresión y escritura

Las propiedades eléctricas del papel tienen gran interés debido al amplio espectro de sus aplicaciones. En este trabajo se han utilizado varios tipos de papel, de fibra virgen y fibra reciclada, con el fin de comprobar si las propiedades eléctricas dependen de la composición fibrosa y el tratamiento al que se ha les ha sometido. La resistencia eléctrica se ha medido utilizando un dispositivo que consta de dos electros de geometría circular, entre los que se coloca el papel. A continuación se establece una diferencia de potencial y se determina directamente la resistencia eléctrica en distintas condiciones de humedad relativa. Se ha validado el método de medida utilizando papel de impresión de 80 g/m2, comprobándose que los valores obtenidos están dentro de los rangos que se indican en la bibliografía. Una vez que se conocen la resistencia eléctrica, el espesor del papel y la sección de los electrodos, se puede determinar la resistividad de los papeles. A partir de estos resultados se ha buscado una relación entre la resistividad y el contenido de humedad, utilizando diversos modelos de regresión cuya validez se analiza en el trabajo. Se ha analizado también la influencia de varias propiedades del papel, como la densidad aparente o el contenido de cenizas, discutiéndose la influencia de estas propiedades en la resistividad

Qualitative screening of 116 veterinary drugs in feed by liquid chromatography-high resolution mass spectrometry. Potential application to quantitative analysis

Veterinarian and human pharmaceuticals may be intentionally added to animal feed to enhance animal production. Monitoring these substances is necessary for protecting the consumers. In this work, a screening method covering 116 human and veterinary drugs has been developed and validated in five types of animal feed at 0.02 and 0.2 mg kg−1. After a simple extraction and dilution, the samples were analysed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Nearly all compounds tested were detected at 0.02 mg kg−1, based on the presence of the accurate-mass (de)protonated molecule. However, the identification using a second accurate-mass ion was more problematic at this level. Finally, the procedure was applied to 22 feed samples, where trimethoprim, robenidine, or α- and β-nandrolone were detected and identified. The potential applicability of the method to quantitative analysis of the compounds detected in the samples was also evaluated

Influencia de la composición fibrosa y las propiedades estructurales del papel prensa en la densidad de la de impresión y la capacidad de secado.

En los últimos años, el papel prensa se fabrica mayoritariamente con fibra reciclada y las rotativas coldset se han convertido en unas instalaciones altamente tecnológicas. En esta nueva situación, los impresores son cada vez más exigentes con el papel que emplean. La calidad de impresión en el papel prensa se evalúa mediante la densidad y la capacidad de secado. El objetivo de este trabajo es establecer cómo influyen la composición fibrosa y las características estructurales del papel en la calidad de impresión. Se seleccionaron diversos papeles prensa, fabricados con fibra virgen y reciclada. Se determinaron las propiedades físicas del papel por métodos clásicos de laboratorio, la absorción de aceite mediante la medición de ángulos de contacto dinámicos y la estructura porosa empleando la porosimetría de intrusión de mercurio. Posteriormente los papeles se imprimieron en el equipo de laboratorio IGT con tinta negra y se evaluó la densidad óptica de la impresión y el repintado. Los resultados de los ensayos clásicos de laboratorio no aportan información sobre el comportamiento del papel durante la impresión. Sin embargo, el tamaño de los poros superficiales y la absorción de aceite explican la densidad de la impresión y la capacidad de secado